Prepubertal Testicular Tumors in Children: Combined Ultrasound and Pathologic Study

Prepubertal Testicular Tumors in Children: Combined Ultrasound and Pathologic Study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Prepubertal Testicular Tumors in Children: Combined Ultrasound and Pathologic Study Ya Ma, Dan Liu, Sijing Ye, Luyu Liu, Yedi Wang, Jiawen Wang, Hongyan Ren This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9115875/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 8 You are reading this latest preprint version Abstract Background Prepubertal testicular tumors represent a distinct clinicopathologic spectrum that differs significantly from adult testicular tumors, necessitating age-specific diagnostic strategies to guide management and preserve testicular function. Purpose This study aimed to characterize the ultrasound (US) features of various histological subtypes of prepubertal testicular tumors and correlate these findings with histopathological results to provide diagnostic clues. Materials and Methods This retrospective study analyzed consecutive pediatric patients with pathologically confirmed testicular tumors at our institution between November 2016 and June 2024. All patients underwent preoperative scrotal US evaluating multiple parameters including tumor size, composition (solid, cystic, mixed), echotexture, vascularity, and calcification. Pathological diagnosis served as the reference standard. Lesions were systematically assessed by correlating US features, such as hyperechoic rings and vascular patterns, with corresponding histological sections. Results The cohort included 118 lesions, with a peak incidence within the first 3 years of life. Benign tumors (e.g., teratoma, epidermoid cyst) constituted 71.2% of cases. A cystic or cystic-dominant US pattern demonstrated a high positive predictive value (PPV) of 96.1% for benignity, but low negative predictive value (NPV) of 47.8%. In contrast, solid or solid-dominant masses exhibited a high NPV for malignancy (91.5%) but a low PPV (49.2%), due to the inclusion of benign entities such as mature teratomas, sex cord-stromal tumors, and hemangiomas. Combining this sonographic pattern (solid and solid-dominant) with AFP >300 ng/mL significantly improved diagnostic performance for yolk sac tumors: PPV 94.7% (95% CI: 71.9–99.7%) and NPV 97.0% (95% CI: 90.8–99.2%). Uncommon entities like juvenile granulosa cell tumors exhibited pathognomonic "swiss-cheese" morphology, while Leydig cell tumors demonstrated infiltrative margins attributed to their unique histopathological growth patterns. Rare metastases and rhabdomyosarcomas presented with distinguishing features that, when combined with clinical context, facilitated accurate diagnosis. Conclusion The combination of high-resolution US and pathological analysis provides a powerful diagnostic framework for prepubertal testicular tumors. Specific US patterns correlate with histologic subtypes and malignant potential. This integrated approach is essential for risk stratification, guiding surgical decisions, and preventing the mismanagement of rare tumor types. child testicular tumor ultrasound imaging Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Testicular tumors represent approximately 1–2% of all pediatric solid malignancies, with an incidence ranging from 0.5 to 2.0 cases per 100,000 children [ 1 , 2 ]. Geographic and racial variations in incidence have been documented, with notably higher rates observed among Asian populations [ 3 ]. Testicular tumors exhibit a bimodal distribution: the first peak occurs before 3 years of age, predominantly comprising benign lesions, while the second peak arises during the postpubertal period (ages 15–19 years), when malignant neoplasms become more prevalent [ 4 ]. While pediatric testicular tumors differ markedly from adult cases in their histological distribution, biological behavior, and clinical prognosis, their clinical presentation is remarkably consistent—most commonly manifesting as a painless scrotal mass [ 5 ]. Less frequent presentations include hydrocele, inguinal hernia, scrotal ecchymosis, or signs of precocious puberty [ 6 ]. Although rare, pediatric testicular tumors pose considerable diagnostic and therapeutic challenges due to their overlapping imaging features, age-specific biological behavior, and the need for individualized management strategies that balance safety with organ preservation. Currently, there is a paucity of large-scale studies correlating ultrasound (US) findings with histopathology in pediatric testicular tumors. This article comprehensively reviews the spectrum of testicular tumors in pediatric patients, with particular emphasis on integrating US features with pathological findings to optimize tumor classification. We discuss both common and rare entities, including germ cell tumors, sex cord-stromal tumors, rhabdomyosarcomas, hemangiomas, and secondary lesions, highlighting not only classic imaging characteristics but also previously underemphasized US findings that may enhance diagnostic accuracy. Materials and Methods This study was approved by the institutional review board of our hospital. A waiver of informed consent was granted as the data were retrospectively collected from electronic medical records. We reviewed the clinical records of patients diagnosed with testicular tumors at our institution between November 2016 and June 2024. Patient Selection Inclusion Criteria : (a) patients aged 0 to 14 years; (b) children diagnosed with testicular tumor confirmed by pathology; (c) preoperative scrotal US available. Exclusion Criteria : (a) incomplete or unavailable clinical, imaging, or pathological data; (b) children with a prior history of testicular tumors or those who had received treatment for such tumors before the study. Demographic, clinical, surgical, and histopathological data were extracted from electronic records, including age at presentation, clinical presentation, serum tumor markers, surgical procedures, and histopathological findings. US Examination All infants underwent detailed scrotal US examinations, using Philips EPIQ 5 (Philips Healthcare, Bothell, WA, USA), Logiq E9 and E11 (GE Healthcare, Boston, MA, USA), and SuperSonic Imagine SA (Aix-en-Provence, France). Linear transducers (5–15 MHz) and curved transducers (5–10 MHz) were used for the examinations. The following parameters were assessed: tumor location and laterality, three diameters of the tumor, tumor borders, echotexture, vascularity, presence of calcifications. Testicular masses were classified according to the relative proportions of solid and cystic components: solid, cystic (cystic mass without solid component), and mixed solid-cystic lesions (both solid and cystic components present). Mixed solid-cystic lesions were further categorized as follows: predominantly solid (solid component larger than cystic component), equal proportion of solid and cystic components, predominantly cystic (the cystic component larger than solid component). Increased blood flow within the solid portion of the tumor may suggest malignancy. The vascularity of the solid components was graded based on Doppler US findings as follows: Grade 0 No vascularity Definition No detectable flow on Doppler. Technical Note: Doppler sensitivity should be optimized (PRF < 1.0 kHz, set gain just below noise threshold). Grade 1 Minimal vascularity Definition 1–2 punctate vessels/cm 2 in the solid component. Grade 2 Moderate vascularity Definition 3–5 vessels/cm 2 in the solid component. Grade 3 Marked vascularity Definition More than 5 vessels/cm 2 in the solid component. Pathological Correlation All histological specimens underwent standardized processing, including hematoxylin-eosin staining and protocol-driven immunohistochemical analysis. Joint evaluation sessions were held between a pediatric pathologist with over 10 years of experience and a radiologist, also with over 10 years of experience. Lesions were systematically assessed by correlating US features, such as hyperechoic rings and vascular patterns, with corresponding histological sections. Statistical Analysis Statistical analysis was performed using Python (version 3.x) with libraries such as pandas, numpy, scipy, and statsmodels. A two-sided p -value of less than 0.05 was considered statistically significant. Categorical variables were presented as frequencies (percentages) and compared using the χ² test or Fisher's exact test, as appropriate. Continuous variables, expressed as medians and interquartile ranges (IQRs), were analyzed using the Mann-Whitney U test. Diagnostic performance of US features and serum markers was evaluated by calculating sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). All measures are reported with their corresponding 95% confidence intervals (95% CI), derived from the Wilson score interval method, implemented using statsmodels. Results Clinical Features A total of 125 pediatric patients with testicular tumors were initially identified between November 2016 and June 2024. After excluding 8 cases with incomplete US data, 117 patients (median age, 27 months; IQR, 8.5–83.5 months) were included in the final analysis. The majority of lesions (n = 65, 55.6%) occurred within the first 3 years of life, with decreasing frequency in older cohorts: 18 patients (15.4%) aged 3–6 years, 16 (13.7%) aged 6–9 years, 15 (12.8%) aged 9–12 years, and 3 (2.6%) aged 12–15 years (Fig. 1 ). The left testis was affected in 62 cases (53.0%), the right in 52 cases (44.4%), and 3 (2.6%) had bilateral involvement, including 2 cases of secondary tumors (Burkitt lymphoma and neuroblastoma) and 1 case of concurrent teratoma and yolk sac tumor (Fig. 2 ). The most common presenting symptom was painless scrotal enlargement or a palpable mass (n = 98, 83.8%). Twelve patients (10.3%) were incidentally detected on US, including 6 cases (5.1%) evaluated for cryptorchidism, 2 of whom had contralateral tumors. Other symptoms included scrotal pain (n = 2, 1.7%), signs of precocious puberty (n = 2, 1.7%, Leydig cell tumors), and prenatally detected intra-abdominal masses (n = 2, 1.7%), which were postnatally confirmed as intra-abdominal testicular teratomas (Fig. 3 ). One 7-month-old boy with neuroblastoma presented with periorbital swelling due to orbital metastases. Associated comorbidities included hydrocele (n = 8, 6.8%), testicular microlithiasis (n = 5, 4.3%), varicocele (n = 2, 1.7%), and inguinal hernia (n = 2, 1.7%). Pathologic Classification One patient with bilateral testicular tumors had distinct pathologies (prepubertal yolk sac tumor and prepubertal teratoma), which were counted as two separate lesions. Two additional patients with bilateral secondary tumors (Burkitt lymphoma and neuroblastoma) were analyzed as single lesions based on the largest mass, as both sides exhibited similar US findings. In total, 118 lesions were included in the analysis. The most common primary benign tumor was mature teratoma, prepubertal type, found in 62 cases (52.5%), followed by epidermoid cyst (n = 12, 10.2%), dermoid cyst (n = 4, 3.4%), Leydig cell tumor (n = 2, 1.7%), hemangioma (n = 2, 1.7%), juvenile granulosa cell tumor (n = 1, 0.8%), Sertoli-Leydig cell tumor (n = 1, 0.8%). The most common primary malignant tumor was yolk sac tumor, prepubertal type, found in 20 cases (16.9%). Other malignant tumors included immature teratomas, prepubertal type (n = 6, 5.1%), rhabdomyosarcoma (n = 2, 1.7%), mixed teratoma and yolk sac tumor, prepubertal type (n = 1, 0.8%), and seminoma (n = 1, 0.8%). Secondary tumors were identified in 4 patients, including 2 cases of acute lymphoblastic leukemia (1.7%), 1 case of Burkitt lymphoma (0.8%) and 1 case of neuroblastoma (0.8%). Both prepubertal teratomas and prepubertal yolk sac tumors peaked in incidence before 3 years of age, with 61.8% of teratomas and 80% of yolk sac tumors occurring in this age group (Fig. 1 ). Tumor Markers and Hormone Levels Serum α-fetoprotein (AFP) was elevated in 19 patients (95.0%) with yolk sac tumors and in 13 patients (19.1%) with teratomas (χ² = 38.456, P < 0.001). The AFP level in yolk sac tumors (median, 3332.50 ng/mL; IQR, 489.86-4767.32 ng/mL) was significantly higher than in teratoma (median, 3.25 ng/mL; IQR, 1.35–42.88 ng/mL) (U = 79.5, P < 0.001). AFP levels were normal in all other tumor types except for a 22-month-old patient with mixed teratoma and yolk sac tumor (AFP = 482.19 ng/mL) and a 2-month-old patient with juvenile granulosa cell tumor (AFP = 244.19 ng/mL). Elevated preoperative testosterone levels were observed in 9 patients (7.6%), including 2 cases of Leydig cell tumor presenting with precocious puberty, 6 cases of teratoma, and 1 case of juvenile granulosa cell tumor. Preoperative β-human chorionic gonadotropin (β-hCG) levels were normal in all patients. US Manifestations and Pathology The clinical, imaging, and pathological findings of testicular tumors in our study are summarized in Table 1 and demonstrated in Fig. 4 . The preoperative US maximum diameter of the lesion ranged from 0.5 to 7 cm (median, 1.9 cm; IQR, 1.1–2.6 cm). Benign tumors (median, 1.4 cm; IQR, 0.9–2.2 cm) were smaller than malignant tumors (median, 2.7 cm; IQR, 2.1–3.6 cm) (U = 79.5, P < 0.001). Cystic lesions were present in 34 cases (28.8%), mixed solid-cystic lesions in 56 cases (47.5%), and solid lesions in 28 cases (23.7%) (Table 2). Tumors were predominantly well-circumscribed (91.5%). Calcification was most commonly observed in teratomas (73.5%) and epidermoid cysts (46.7%), and also noted in 1 dermoid cyst, 1 yolk sac tumor, and 1 Sertoli-Leydig cell tumor. “Onion-ring” appearance was noted in 3 epidermoid cysts (25.5%), 2 dermoid cysts (50.0%), and 4 mature teratomas (6.5%). Hyperechoic rings were observed in 4 epidermoid cysts (33.3%) and 1 dermoid cyst (25.0%), arising from collagen-rich tissue creating an acoustic interface. Homogeneous echogenicity with solid components was observed in 23/84 (27.4%) of non-pure cystic lesions, predominantly yolk sac tumors (n = 15). Other homogeneous tumors included 1 mixed teratoma and yolk sac tumor, 1 Leydig cell tumor, 1 hemangioma, 1 rhabdomyosarcoma, and 4 secondary tumors. All purely cystic and 88.2% of cystic-dominant lesions were benign, including teratomas, epidermoid cysts, dermoid cysts, and juvenile granulosa cell tumors. Two cases of immature teratomas were exceptions, with predominantly cystic lesions. The PPV of cystic and cystic-dominant lesions for benign tumors was 96.1% (95% CI: 85.4–99.3%), but the NPV was low (47.8%, 95% CI: 35.6–60.2%). Most malignant tumors were solid or solid-dominant, with the exception of 5 cases of immature teratomas (2 predominantly cystic and 3 with equal proportions of solid and cystic components). The NPV of solid and solid-dominant lesions for malignancy was 91.5% (95% CI: 80.6–96.8%), while the PPV was low (49.2%, 95% CI: 36.1–62.4%). Combining this sonographic pattern (solid and solid-dominant) with AFP > 300 ng/mL significantly improved diagnostic performance for yolk sac tumors (including mixed teratoma and yolk sac tumor): PPV 94.7% (95% CI: 71.9–99.7%) and NPV 97.0% (95% CI: 90.8–99.2%). All Leydig cell tumors (n = 2), hemangiomas (n = 2), and the Sertoli-Leydig cell tumor (n = 1) were solid. Leydig cell tumors and hemangiomas in this cohort were relatively small, with all measuring less than 2 cm. Both Leydig cell tumors presented as ill-defined hypoechoic masses with a hyperechoic rim. Secondary tumors (n = 4) uniformly presented as purely solid hypoechoic masses. Two rhabdomyosarcomas were identified. The first, an embryonal subtype, appeared as a homogeneous solid mass without cystic or calcified components and was initially misdiagnosed as a yolk sac tumor. The second, a spindle cell variant, presented as a large, predominantly solid lesion with heterogeneous echotexture, no calcification, and prominent vascularity. Additionally, a 10-month-old boy with seminoma had an ill-defined, hypoechoic intratesticular mass, characterized by heterogeneous echotexture and increased vascularity. Differentiation between Teratoma and Yolk Sac Tumor We specifically compared teratoma and yolk sac tumor as they represent the most common benign and malignant prepubertal testicular germ cell tumors, respectively. US characteristics of teratomas and yolk sac tumors are summarized in Table 3. Teratomas demonstrated a remarkably wide morphologic spectrum, with cases identified across all five sonographic classification categories: purely solid, purely cystic, and all three subcategories of mixed lesions (predominantly solid, balanced, and predominantly cystic) (Fig. 5 ). Yolk sac tumors were significantly larger than teratomas (median 2.6 cm vs 1.6 cm, P < 0.001) and with a higher likelihood of solid architecture (60% vs 7.4%, P < 0.001). They were predominantly homogeneous (75.0% vs 0.0%, P < 0.001), hypervascular (100.0% vs 5.9%, P < 0.001) with less frequent calcification (5.0% vs 73.5%, P < 0.001). While all teratomas and most yolk sac tumors (85%) exhibited well-defined borders, yolk sac tumors more commonly exhibited poorly defined margins (15%), suggesting infiltrative growth or abnormal vascular supply, indicative of a more aggressive phenotype. Discussion It is evident that testicular tumors in childhood differ significantly from those in adolescence and adulthood, both in terms of incidence and histological characteristics, necessitating age-specific diagnostic frameworks. This retrospective cohort study establishes critical imaging-histology correlations that refine diagnostic pathways and guide management decisions for prepubertal testicular tumors. In our cohort, 71.8% of prepubertal tumors were benign, consistent with previous reports (74%) [ 7 ]. Cystic or cystic-dominant lesions demonstrated a near-perfect PPV for benignity (96.1%), predominantly mature teratomas and epidermoid cysts. This finding aligns with the European Society for Pediatric Urology (ESPU) guidelines, which recommend testis-sparing surgery for such lesions [ 8 ]. In contrast, solid or solid-dominant masses exhibited a high NPV for malignancy (91.5%) but a low PPV (49.2%) due to the inclusion of benign entities such as mature teratomas, sex cord-stromal tumors, and hemangiomas. Epidermoid and dermoid cysts, both originating from ectodermal elements, typically appear as well-defined, avascular masses. The classic "onion-ring" sign, characterized by concentric layers of alternating echogenicity, is highly suggestive of epidermoid cysts, though this feature is not always present and may occasionally be observed in teratomas. Hyperechoic ring is another key indicator of epidermoid cysts, though mixed echogenicity or calcification may complicate differentiation from teratomas. Prepubertal-type teratomas, not associated with Germ Cell Neoplasia In Situ (GCNIS), usually have an excellent prognosis with very low malignancy risk. As the most frequent pediatric testicular tumor, they demonstrate a remarkably wide morphologic spectrum, reflecting their composition of tissues from all three germ layers. The imaging features of mature and immature teratomas often overlap. Solid components appear more heterogeneous depending on the presence of different tissue types like cartilage, fibrous tissue, and adipose content. The cystic elements are not limited to the digestive or respiratory epithelia that produce mucus or digestive fluids (appearing as hypoechoic fluid with debris or a "ground-glass" echotexture), but may originate from various epithelium-lined structures derived from all three germ layers. For example, ectoderm-derived tissues like epidermis and choroid plexus may form keratin debris (manifesting as hyper-hypoechoic rings) or cerebrospinal fluid-like content (appearing as anechoic fluid). In rare cases, intra-abdominal testicular tumors could be suspected in infants presenting with abdominal mass/pain (potentially due to torsion) and undescended homolateral testis [ 9 ]. While most intra-abdominal testicular tumors in prepubertal children are teratomas, exceptional cases of yolk sac tumor have been documented [ 10 ]. Yolk sac tumors are the most common malignant testicular germ-cell tumors in prepubertal children, with an incidence ranging from 8% to 30% [ 11 ]. Elevated serum AFP levels are present in 95–98% of cases [ 12 ], typically exceeding 100 ng/mL [ 13 ]. In our cohort, AFP was elevated in 95% of yolk sac tumors, with most values exceeding 300 ng/mL. US typically shows a large, round, or ovoid, solid, homogeneous mass that can completely occupy the affected testis, often with hypervascularity on color Doppler. Microcysts, identified in 40% of our yolk sac tumor cases, represented distinct histopathological structures rather than true epithelial-lined cysts and corresponded to regions of hemorrhagic necrosis. Leydig cell tumors represent the most common sex cord-stromal tumors in children, followed by juvenile granulosa cell tumors. Leydig cell tumors typically occur between 5 and 10 years of age and present with precocious puberty secondary to excessive testosterone production. On US, they appear as isolated hypoechoic, hypervascular masses without calcification [ 14 ]. In our series, both Leydig cell tumors demonstrated poorly defined margins with a hyperechoic rim, which can be attributed to their infiltrative, non-encapsulated growth pattern, that blends with seminiferous tubules. Differentiating Leydig cell tumors from testicular adrenal rest tumors (TARTs) is crucial, as both can present as hypoechoic masses with hormonal activity but require divergent management. TARTs typically present as bilateral peri-mediastinal lesions that may demonstrate a multilocular pattern without significant mass effect, with vascularity ranging from intense to minimal [ 15 ]. Juvenile granulosa cell tumors are the most common congenital testicular tumors, typically occurring within the first 6 months of life and rarely diagnosed prenatally [ 16 ]. These benign, hormonally inactive lesions rarely recur after testis-sparing surgery [ 17 ]. On US, they characteristically present as well-encapsulated, multicystic masses with thick septations, resembling "Swiss cheese". These features correspond histologically to follicular structures containing basophilic or eosinophilic material, sometimes with hemorrhagic foci [ 18 ]. Color Doppler imaging demonstrates hypervascularity within solid components and septations [ 19 ]. The early age of onset and normal or mildly elevated AFP levels (distinct from the marked elevation in yolk sac tumors) provide valuable diagnostic clues [ 18 ]. Leukemia and lymphoma are the most common secondary testicular tumors in children. Among these, leukemia, particularly acute lymphoblastic leukemia (ALL), is the most prevalent. Testicular involvement is often a key indicator of relapse in these cases. US typically shows unilateral or bilateral testicular enlargement with homogeneous hypoechoic infiltration while preserving testicular contour. Color Doppler imaging reveals increased flow with a normal rectilinear course [ 20 – 23 ]. Histopathologically, these malignancies present as dense, monotonous sheets of small, round blue cells, resulting in uniform acoustic interfaces. These cells infiltrate the normal seminiferous tubules without forming distinct masses, while the blood vessel framework remains preserved. The bilateral testicular metastases observed in our cohort offer insights into neuroblastoma dissemination. To our knowledge, only a few similar cases have been documented. In this case, primary neuroblastomas appeared heterogeneous due to necrosis, calcification, and hemorrhage, whereas testicular metastases exhibited a homogeneous, hypoechoic appearance, a finding likely attributable to cellular selection during passage through blood-tissue barriers. Testicular hemangiomas are extremely rare and can mimic both benign and malignant lesions. In our study, two capillary hemangiomas appeared predominantly hypoechoic with tangled vascular channels, and color Doppler revealed marked intralesional hypervascularity. Unlike malignancies, which exhibit irregular and chaotic patterns, hemangiomas demonstrate organized vascular structures. Accurate preoperative diagnosis is essential to avoid unnecessary radical surgery. Paratesticular rhabdomyosarcoma accounts for 7% of all rhabdomyosarcomas, with a bimodal age distribution (peaks at 5 and 16 years) and a median diagnosis age of 7 years [ 20 , 24 ]. Embryonal rhabdomyosarcomas account for 90% of pediatric cases. In our cohort, the embryonal subtype presented as a homogeneous hypoechoic mass, mimicking the solid appearance of yolk sac tumors. These tumors are characterized by densely packed tumor cells with sparse stroma, resulting in homogeneous hypoechoic sonographic features. Normal AFP levels provide crucial diagnostic differentiation. In contrast, the spindle cell subtype manifested as a heterogeneous mass with microcysts, suggesting a myxoid extracellular matrix or ischemic necrosis. While this study provides valuable insights into the clinical, pathological, and US features of pediatric testicular tumors, its retrospective design and single-center data limit generalizability. Future multicenter prospective studies with larger cohorts are needed to validate these findings. Further exploration of molecular markers and advanced imaging techniques, such as contrast-enhanced US [ 25 ], may enhance diagnostic accuracy and management. In conclusion, the integration of US and pathological analysis offers a comprehensive diagnostic framework for pediatric testicular tumors. Benign lesions are typically characterized by predominantly cystic components, well-defined borders, echogenic rims, or organized vascular patterns. Malignancy should be suspected when US shows solid-dominant masses with chaotic vascularity, particularly when accompanied by elevated AFP. Uncommon entities—such as neuroblastoma metastases, hemangiomas, or paratesticular rhabdomyosarcoma—though rare, exhibit distinctive sonographic and pathological features that help narrow the differential diagnosis. Declarations Author Contribution Y.M. designed the study and wrote the main manuscript text. 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AJR Am J Roentgenol. ;164(3):645-7. 10.2214/ajr.164.3.7863887 . PMID: 7863887 Yang L, Tao Y, Weixin Z, Meiling B, Jing H (2022) Contrast-enhanced and microvascular ultrasound imaging features of testicular lymphoma: report of five cases and review literature. BMC Urol 22(1):6. 10.1186/s12894-022-00957-1 PMID: 35067228; PMCID: PMC8785503 Bertolotto M, Derchi LE, Secil M, Dogra V, Sidhu PS, Clements R, Freeman S, Grenier N, Mannelli L, Ramchandani P, Cicero C, Abete L, Bussani R, Rocher L, Spencer J, Tsili A, Valentino M, Pavlica P (2015) European Society of Urogenital Radiology Scrotal Imaging Subcommittee. Grayscale and color Doppler features of testicular lymphoma. J Ultrasound Med 34(6):1139–1145. 10.7863/ultra.34.6.1139 PMID: 26014335; PMCID: PMC4977091 Walterhouse DO, Barkauskas DA, Hall D, Ferrari A, De Salvo GL, Koscielniak E, Stevens MCG, Martelli H, Seitz G, Rodeberg DA, Shnorhavorian M, Dasgupta R, Breneman JC, Anderson JR, Bergeron C, Bisogno G, Meyer WH, Hawkins DS, Minard-Colin V (2018) Demographic and Treatment Variables Influencing Outcome for Localized Paratesticular Rhabdomyosarcoma: Results From a Pooled Analysis of North American and European Cooperative Groups. J Clin Oncol 36(35):JCO2018789388 Epub ahead of print. PMID: 30351998; PMCID: PMC6286163 Sidhu PS, Cantisani V, Dietrich CF, Gilja OH, Saftoiu A, Bartels E, Bertolotto M, Calliada F, Clevert DA, Cosgrove D, Deganello A, D'Onofrio M, Drudi FM, Freeman S, Harvey C, Jenssen C, Jung EM, Klauser AS, Lassau N, Meloni MF, Leen E, Nicolau C, Nolsoe C, Piscaglia F, Prada F, Prosch H, Radzina M, Savelli L, Weskott HP, Wijkstra H (2018) The EFSUMB Guidelines and Recommendations for the Clinical Practice of Contrast-Enhanced Ultrasound (CEUS) in Non-Hepatic Applications: Update 2017 (Long Version). Ultraschall Med. ;39(2):e2-e44. English. 10.1055/a-0586-1107 . Epub 2018 Mar 6. PMID: 29510439 Tables Table 1: Clinical, US, and histopathological characteristics of prepubertal testicular tumors Tumor histotype n (%) Age (month) Maximum diameter (cm) Tumor markers and hormone levels US characteristics Pathological correlation Epidermoid cyst and Dermoid cyst 16 (13.6) Median, 76.5; IQR, 28.0-76.5 Median, 0.9; IQR, 0.6-1.3 Usually without hormonal activity Well-defined, round or oval avascular lesion. "Onion-ring" appearance of multiple concentric layers of alternating echogenicity. May have a hyperechoic ring. Well-demarcated mixed echogenic lesion with or without calcifications. Keratin-producing epithelium is responsible for the keratin accumulation within the lumen of the cyst that appears hyperechoic on US. Dermoid cysts differ from epidermoid cysts in that they contain skin appendages, such as hair follicles and sebaceous glands. Teratoma, prepubertal type 68 (57.6) Peak incidence before 3 years of age Median, 1.6; IQR, 1.1-2.6 AFP: may be mildly elevated Wide spectrum: Ranging from predominantly cystic to predominantly solid lesions, though most demonstrate mixed solid-cystic architecture. Calcification is common. Well-defined margins. The relative proportions of cystic elements (e.g., serous or mucinous fluid), solid tissues (e.g., mesenchymal stroma, glial tissue), and calcifications directly influence their echogenic properties, leading to a spectrum of echogenic patterns ranging from anechoic cysts to complex, heterogeneous masses. Yolk sac tumor, prepubertal type 20 (16.9) Peak incidence before 3 years of age Median, 2.6; IQR, 2.0-3.3 AFP: markedly elevated Ovoid, homogeneous solid lesion with isoechoic to hypoechoic echotexture. Prominent hypervascularity. Microcysts may be present, but conspicuous cystic areas are usually absent unless the tumor is larger. Calcification seldom occers. The uniformity of the US features correlates with the dense cellular architecture of the tumor at the histological level. Lack significant fluid or cystic components, although occasional evident hemorrhage or necrosis may be present. Leydig cell tumor 2 (1.7) 58; 68 1.3; 0.5 Typically with levated testosterone Presents as a small, solid, hypoechoic mass. May demonstrate ill-defined margins with a peripheral hyperechoic rim. Color Doppler imaging reveals intralesional hypervascularity. Tumors lack a true fibrous capsule, with tumor cells infiltrating between seminiferous tubules and blending with the normal parenchyma. Juvenile granulosa cell tumor 1 (0.8) 2 3.9 Usually without hormonal activity "Swiss cheese" multilocular pattern mass. Solid components are typically hypoechoic or isoechoic and demonstrate increased vascularity. Tumors are characterized by multiple cystic spaces, formed by fluid accumulation from neoplastic granulosa cells. These cysts are usually lined with granulosa cells and may include areas of hemorrhage or necrosis. Hemangioma 2 (1.7) 81; 112 1.9; 0.7 Usually without hormonal activity Predominantly hypoechoic masses demonstrating prominent, organized intralesional hypervascularity. Hemangiomas are composed of clusters of blood vessels, which form a tangled network of vascular channels. Secondary tumor 4 (3.4) 7; 85; 89; 127 3.5; 3.6; 2.5; 4 Usually without hormonal activity Unilateral or bilateral. Testes present a big size with diffuse or focal homogeneous hypoechoic infiltration. Preserved testicular shape. Usually hypervascular while maintaining normal vascular course and branching patterns. Diffuse infiltration of monotonous sheets of small, round blue cells results in a homogeneous tissue architecture, creating uniform acoustic interfaces on US. AFP, alpha-fetoprotein. Table 2. Distribution of tumor histotypes according to US classification of tumor components Classification of tumor components Tumor histotype n (%) Cystic 34 (28.8%) Mature teratoma, prepubertal type 18 (52.9) Epidermoid cyst 12 (35.2) Dermoid cyst 4 (11.8) Predominantly cystic 17 (14.4%) Mature teratoma, prepubertal type 14 (82.4) Immature teratomas, prepubertal type 2 (11.8) Juvenile granulosa cell tumor 1 (5.9) Equal proportion of solid and cystic components 8 (6.8%) Mature teratoma, prepubertal type 5 (62.5) Immature teratomas, prepubertal type 3 (37.5) Predominantly solid 31 (26.3%) Mature teratoma, prepubertal type 20 (64.5) Yolk sac tumor, prepubertal type 8 (25.8) Immature teratomas, prepubertal type 1 (3.2) Rhabdomyosarcoma 1 (3.2) Mixed teratoma and yolk sac tumor, prepubertal type 1 (3.2) Solid 28 (23.7%) Yolk sac tumor, prepubertal type 12 (42.9) Mature teratoma, prepubertal type 5 (17.9) Secondary tumor 4 (14.3) Leydig cell tumor 2 (7.1) Hemangioma 2 (7.1) Seminoma 1 (3.6) Sertoli-Leydig cell tumor 1 (3.6) Rhabdomyosarcoma 1 (3.6) Table 3: US features of prepubertal teratoma and yolk sac tumor Parameters Teratoma, prepubertal type Yolk sac tumor, prepubertal type Statistic P value Maximum diameter (cm), median (IQR) 1.6 (1.1, 2.6) 2.6 (2.0, 3.3) U=364.00 0.002 Laterality χ2=0.549 0.459 Right (%) 31/68 (45.6) 11/20 (55.0) Left (%) 37/68 (54.4) 9/20 (45.0) Tumor components χ2=23.63 ＜0.001 Cystic (%) 18/68 (26.5) 0/20 (0.0) Predominantly cystic (%) 16/68 (23.5) 0/20 (0.0) Equal proportion of solid and cystic components (%) 8/68 (11.8) 0/20 (0.0) Predominantly solid (%) 21/68 (30.9) 8/20 (40.0) Solid (%) 5/68 (7.4) 12/20 (60.0) Border 0.01 Well-defined 68/68 (100.0) 17/20 (85.0) Poorly defined 0/68 (0.0) 3/20 (15.0) Homogeneity of solid components (Teratoma, n=50; Yolk sac tumor, n=20) χ2=43.38 ＜0.001 Homogeneous 0/50 (0.0) 15/20 (75.0) Heterogeneous 50/50 (100.00) 5/20 (25.0) Calcification (%) 50/68 (73.5) 1/20 (5.0) χ2=29.79 ＜0.001 Vascularity χ2=69.02 ＜0.001 Grade 0 43/68 (63.2) 0/20 (0.0) Grade 1 18/68 (26.5) 0/20 (0.0) Grade 2 3/68 (4.4) 0/20 (0.0) Grade 3 4/68 (5.9) 20/20 (100.0) Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 10 May, 2026 Reviewers agreed at journal 02 May, 2026 Reviews received at journal 13 Apr, 2026 Reviewers agreed at journal 26 Mar, 2026 Reviewers invited by journal 23 Mar, 2026 Editor assigned by journal 16 Mar, 2026 Submission checks completed at journal 16 Mar, 2026 First submitted to journal 13 Mar, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9115875","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":610360870,"identity":"a6c4a7e7-8c7b-4435-a0fa-bef088386cb6","order_by":0,"name":"Ya Ma","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAuElEQVRIiWNgGAWjYFAC5sOP//DY8PDzNxCthS3NgEcmTUZyxgGitfAYSPDYHLYxaEggUoPujBwDA4mc8zwGDAcYP3zMIUKL2Y20ggcGZ27zmDM3MEvO3EaUluQNBok9t3ksGw6wMfMSpyXBQOLgv3M8BgcSiNaSYiDZwHOAFC1nnqUZM/Ak80jOONhMpF+OJx9+zMBjZ8/P33zww0ditDAIJMBYjA3EqAcC/gNEKhwFo2AUjIKRCwCd6DeZENfLUAAAAABJRU5ErkJggg==","orcid":"","institution":"Capital Center for Children's Health, Capital Medical University","correspondingAuthor":true,"prefix":"","firstName":"Ya","middleName":"","lastName":"Ma","suffix":""},{"id":610360872,"identity":"36154ca9-d3a4-4634-8dc2-1412355b7c79","order_by":1,"name":"Dan Liu","email":"","orcid":"","institution":"Capital Center for Children's Health, Capital Medical University","correspondingAuthor":false,"prefix":"","firstName":"Dan","middleName":"","lastName":"Liu","suffix":""},{"id":610360874,"identity":"8495c343-cb3f-42d2-96e4-78a7a4cbf645","order_by":2,"name":"Sijing Ye","email":"","orcid":"","institution":"Capital Institute of Pediatrics","correspondingAuthor":false,"prefix":"","firstName":"Sijing","middleName":"","lastName":"Ye","suffix":""},{"id":610360876,"identity":"a88db29f-7939-4c29-9acd-d5cf6e7b0d12","order_by":3,"name":"Luyu Liu","email":"","orcid":"","institution":"Capital Center for Children's Health, Capital Medical University","correspondingAuthor":false,"prefix":"","firstName":"Luyu","middleName":"","lastName":"Liu","suffix":""},{"id":610360877,"identity":"2d901abb-4e0d-4779-a236-89921ecc527d","order_by":4,"name":"Yedi Wang","email":"","orcid":"","institution":"Capital Center for Children's Health, Capital Medical University","correspondingAuthor":false,"prefix":"","firstName":"Yedi","middleName":"","lastName":"Wang","suffix":""},{"id":610360878,"identity":"5eb2b7a0-e832-4c98-934c-e84af7a683ed","order_by":5,"name":"Jiawen Wang","email":"","orcid":"","institution":"Capital Institute of Pediatrics","correspondingAuthor":false,"prefix":"","firstName":"Jiawen","middleName":"","lastName":"Wang","suffix":""},{"id":610360879,"identity":"713cda8f-81dc-4204-a1a5-de0e26c3422c","order_by":6,"name":"Hongyan Ren","email":"","orcid":"","institution":"Capital Center for Children's Health, Capital Medical University","correspondingAuthor":false,"prefix":"","firstName":"Hongyan","middleName":"","lastName":"Ren","suffix":""}],"badges":[],"createdAt":"2026-03-13 14:39:41","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9115875/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9115875/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":105410196,"identity":"ff2a9f37-50dc-4139-be6c-b9f8e8cdc65b","added_by":"auto","created_at":"2026-03-25 17:15:39","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":67190,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eAge distribution of prepubertal testicular tumors.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"image1.png","url":"https://assets-eu.researchsquare.com/files/rs-9115875/v1/9de1dd8848a43d7a36528e0f.png"},{"id":105410194,"identity":"f580d27f-573f-44f9-b74b-487db36c4e71","added_by":"auto","created_at":"2026-03-25 17:15:38","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":362775,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eConcurrent prepubertal teratoma and yolk sac tumor in a 10-month-old boy. \u003c/strong\u003e(A) Left testis US shows a complex solid-cystic mass with calcifications (arrow), consistent with teratoma. (B) Left testis US demonstrates a solid, homogeneous mass, characteristic of a yolk sac tumor.\u003c/p\u003e","description":"","filename":"image2.png","url":"https://assets-eu.researchsquare.com/files/rs-9115875/v1/1c380d515e29b5ea23112ab8.png"},{"id":105751838,"identity":"4ce87c5e-110e-4de8-b3e6-a20eae0fbe50","added_by":"auto","created_at":"2026-03-30 15:47:19","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":647324,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eIntra-abdominal testicular teratoma in a 15-day-old boy. \u003c/strong\u003e(A) Postnatal abdominal US reveals a well-defined, predominantly cystic mass with internal solid components and calcifications (arrow) in the left lower quadrant. (B) Transverse US shows the mass (M) is situated to the left of the bladder (BL). (C) Scrotal US demonstrates an empty left hemiscrotum, confirming ipsilateral cryptorchidism. (D) The right testis appears normal, with a small hydrocele (arrow).\u003c/p\u003e","description":"","filename":"image3.png","url":"https://assets-eu.researchsquare.com/files/rs-9115875/v1/1faefadfb0102e2e4e8630d4.png"},{"id":105410195,"identity":"6b04e2d4-2123-48fa-8152-f393b996a93e","added_by":"auto","created_at":"2026-03-25 17:15:38","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1339101,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eRepresentative US and histopathological features of prepubertal testicular tumors.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"image4.png","url":"https://assets-eu.researchsquare.com/files/rs-9115875/v1/33d0915397e8e0ce19929236.png"},{"id":105410191,"identity":"70cd55d6-27d8-4ff3-9b8a-e73a694a0a7f","added_by":"auto","created_at":"2026-03-25 17:15:38","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":454798,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eMorphologic spectrum of prepubertal teratomas\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"image5.png","url":"https://assets-eu.researchsquare.com/files/rs-9115875/v1/3539289643c3c67ce5536d32.png"},{"id":106095526,"identity":"d2d2db55-23bc-496d-bc56-8fd8e4b10b52","added_by":"auto","created_at":"2026-04-03 11:48:32","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4540311,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9115875/v1/584dbadb-749f-4e0a-a24f-04e47315ebfd.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Prepubertal Testicular Tumors in Children: Combined Ultrasound and Pathologic Study","fulltext":[{"header":"Introduction","content":"\u003cp\u003eTesticular tumors represent approximately 1\u0026ndash;2% of all pediatric solid malignancies, with an incidence ranging from 0.5 to 2.0 cases per 100,000 children [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Geographic and racial variations in incidence have been documented, with notably higher rates observed among Asian populations [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Testicular tumors exhibit a bimodal distribution: the first peak occurs before 3 years of age, predominantly comprising benign lesions, while the second peak arises during the postpubertal period (ages 15\u0026ndash;19 years), when malignant neoplasms become more prevalent [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. While pediatric testicular tumors differ markedly from adult cases in their histological distribution, biological behavior, and clinical prognosis, their clinical presentation is remarkably consistent\u0026mdash;most commonly manifesting as a painless scrotal mass [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Less frequent presentations include hydrocele, inguinal hernia, scrotal ecchymosis, or signs of precocious puberty [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAlthough rare, pediatric testicular tumors pose considerable diagnostic and therapeutic challenges due to their overlapping imaging features, age-specific biological behavior, and the need for individualized management strategies that balance safety with organ preservation. Currently, there is a paucity of large-scale studies correlating ultrasound (US) findings with histopathology in pediatric testicular tumors.\u003c/p\u003e \u003cp\u003eThis article comprehensively reviews the spectrum of testicular tumors in pediatric patients, with particular emphasis on integrating US features with pathological findings to optimize tumor classification. We discuss both common and rare entities, including germ cell tumors, sex cord-stromal tumors, rhabdomyosarcomas, hemangiomas, and secondary lesions, highlighting not only classic imaging characteristics but also previously underemphasized US findings that may enhance diagnostic accuracy.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e This study was approved by the institutional review board of our hospital. A waiver of informed consent was granted as the data were retrospectively collected from electronic medical records. We reviewed the clinical records of patients diagnosed with testicular tumors at our institution between November 2016 and June 2024.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003ePatient Selection\u003c/h2\u003e \u003cp\u003e \u003cb\u003eInclusion Criteria\u003c/b\u003e: (a) patients aged 0 to 14 years; (b) children diagnosed with testicular tumor confirmed by pathology; (c) preoperative scrotal US available. \u003cb\u003eExclusion Criteria\u003c/b\u003e: (a) incomplete or unavailable clinical, imaging, or pathological data; (b) children with a prior history of testicular tumors or those who had received treatment for such tumors before the study.\u003c/p\u003e \u003cp\u003eDemographic, clinical, surgical, and histopathological data were extracted from electronic records, including age at presentation, clinical presentation, serum tumor markers, surgical procedures, and histopathological findings.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eUS Examination\u003c/h3\u003e\n\u003cp\u003eAll infants underwent detailed scrotal US examinations, using Philips EPIQ 5 (Philips Healthcare, Bothell, WA, USA), Logiq E9 and E11 (GE Healthcare, Boston, MA, USA), and SuperSonic Imagine SA (Aix-en-Provence, France). Linear transducers (5\u0026ndash;15 MHz) and curved transducers (5\u0026ndash;10 MHz) were used for the examinations.\u003c/p\u003e \u003cp\u003eThe following parameters were assessed: tumor location and laterality, three diameters of the tumor, tumor borders, echotexture, vascularity, presence of calcifications.\u003c/p\u003e \u003cp\u003eTesticular masses were classified according to the relative proportions of solid and cystic components: solid, cystic (cystic mass without solid component), and mixed solid-cystic lesions (both solid and cystic components present). Mixed solid-cystic lesions were further categorized as follows: predominantly solid (solid component larger than cystic component), equal proportion of solid and cystic components, predominantly cystic (the cystic component larger than solid component).\u003c/p\u003e \u003cp\u003eIncreased blood flow within the solid portion of the tumor may suggest malignancy. The vascularity of the solid components was graded based on Doppler US findings as follows:\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eGrade 0\u003c/strong\u003e \u003cp\u003eNo vascularity\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eDefinition\u003c/strong\u003e \u003cp\u003eNo detectable flow on Doppler.\u003c/p\u003e \u003c/p\u003e \u003cp\u003eTechnical Note: Doppler sensitivity should be optimized (PRF\u0026thinsp;\u0026lt;\u0026thinsp;1.0 kHz, set gain just below noise threshold).\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eGrade 1\u003c/strong\u003e \u003cp\u003eMinimal vascularity\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eDefinition\u003c/strong\u003e \u003cp\u003e1\u0026ndash;2 punctate vessels/cm\u003csup\u003e2\u003c/sup\u003e in the solid component.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eGrade 2\u003c/strong\u003e \u003cp\u003eModerate vascularity\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eDefinition\u003c/strong\u003e \u003cp\u003e3\u0026ndash;5 vessels/cm\u003csup\u003e2\u003c/sup\u003e in the solid component.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eGrade 3\u003c/strong\u003e \u003cp\u003eMarked vascularity\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eDefinition\u003c/strong\u003e \u003cp\u003eMore than 5 vessels/cm\u003csup\u003e2\u003c/sup\u003e in the solid component.\u003c/p\u003e \u003c/p\u003e\n\u003ch3\u003ePathological Correlation\u003c/h3\u003e\n\u003cp\u003eAll histological specimens underwent standardized processing, including hematoxylin-eosin staining and protocol-driven immunohistochemical analysis. Joint evaluation sessions were held between a pediatric pathologist with over 10 years of experience and a radiologist, also with over 10 years of experience. Lesions were systematically assessed by correlating US features, such as hyperechoic rings and vascular patterns, with corresponding histological sections.\u003c/p\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eStatistical analysis was performed using Python (version 3.x) with libraries such as pandas, numpy, scipy, and statsmodels. A two-sided \u003cem\u003ep\u003c/em\u003e-value of less than 0.05 was considered statistically significant. Categorical variables were presented as frequencies (percentages) and compared using the χ\u0026sup2; test or Fisher's exact test, as appropriate. Continuous variables, expressed as medians and interquartile ranges (IQRs), were analyzed using the Mann-Whitney U test. Diagnostic performance of US features and serum markers was evaluated by calculating sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). All measures are reported with their corresponding 95% confidence intervals (95% CI), derived from the Wilson score interval method, implemented using statsmodels.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eClinical Features\u003c/h2\u003e \u003cp\u003eA total of 125 pediatric patients with testicular tumors were initially identified between November 2016 and June 2024. After excluding 8 cases with incomplete US data, 117 patients (median age, 27 months; IQR, 8.5\u0026ndash;83.5 months) were included in the final analysis. The majority of lesions (n\u0026thinsp;=\u0026thinsp;65, 55.6%) occurred within the first 3 years of life, with decreasing frequency in older cohorts: 18 patients (15.4%) aged 3\u0026ndash;6 years, 16 (13.7%) aged 6\u0026ndash;9 years, 15 (12.8%) aged 9\u0026ndash;12 years, and 3 (2.6%) aged 12\u0026ndash;15 years (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The left testis was affected in 62 cases (53.0%), the right in 52 cases (44.4%), and 3 (2.6%) had bilateral involvement, including 2 cases of secondary tumors (Burkitt lymphoma and neuroblastoma) and 1 case of concurrent teratoma and yolk sac tumor (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe most common presenting symptom was painless scrotal enlargement or a palpable mass (n\u0026thinsp;=\u0026thinsp;98, 83.8%). Twelve patients (10.3%) were incidentally detected on US, including 6 cases (5.1%) evaluated for cryptorchidism, 2 of whom had contralateral tumors. Other symptoms included scrotal pain (n\u0026thinsp;=\u0026thinsp;2, 1.7%), signs of precocious puberty (n\u0026thinsp;=\u0026thinsp;2, 1.7%, Leydig cell tumors), and prenatally detected intra-abdominal masses (n\u0026thinsp;=\u0026thinsp;2, 1.7%), which were postnatally confirmed as intra-abdominal testicular teratomas (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). One 7-month-old boy with neuroblastoma presented with periorbital swelling due to orbital metastases. Associated comorbidities included hydrocele (n\u0026thinsp;=\u0026thinsp;8, 6.8%), testicular microlithiasis (n\u0026thinsp;=\u0026thinsp;5, 4.3%), varicocele (n\u0026thinsp;=\u0026thinsp;2, 1.7%), and inguinal hernia (n\u0026thinsp;=\u0026thinsp;2, 1.7%).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003ePathologic Classification\u003c/h3\u003e\n\u003cp\u003eOne patient with bilateral testicular tumors had distinct pathologies (prepubertal yolk sac tumor and prepubertal teratoma), which were counted as two separate lesions. Two additional patients with bilateral secondary tumors (Burkitt lymphoma and neuroblastoma) were analyzed as single lesions based on the largest mass, as both sides exhibited similar US findings. In total, 118 lesions were included in the analysis.\u003c/p\u003e \u003cp\u003eThe most common primary benign tumor was mature teratoma, prepubertal type, found in 62 cases (52.5%), followed by epidermoid cyst (n\u0026thinsp;=\u0026thinsp;12, 10.2%), dermoid cyst (n\u0026thinsp;=\u0026thinsp;4, 3.4%), Leydig cell tumor (n\u0026thinsp;=\u0026thinsp;2, 1.7%), hemangioma (n\u0026thinsp;=\u0026thinsp;2, 1.7%), juvenile granulosa cell tumor (n\u0026thinsp;=\u0026thinsp;1, 0.8%), Sertoli-Leydig cell tumor (n\u0026thinsp;=\u0026thinsp;1, 0.8%). The most common primary malignant tumor was yolk sac tumor, prepubertal type, found in 20 cases (16.9%). Other malignant tumors included immature teratomas, prepubertal type (n\u0026thinsp;=\u0026thinsp;6, 5.1%), rhabdomyosarcoma (n\u0026thinsp;=\u0026thinsp;2, 1.7%), mixed teratoma and yolk sac tumor, prepubertal type (n\u0026thinsp;=\u0026thinsp;1, 0.8%), and seminoma (n\u0026thinsp;=\u0026thinsp;1, 0.8%). Secondary tumors were identified in 4 patients, including 2 cases of acute lymphoblastic leukemia (1.7%), 1 case of Burkitt lymphoma (0.8%) and 1 case of neuroblastoma (0.8%).\u003c/p\u003e \u003cp\u003eBoth prepubertal teratomas and prepubertal yolk sac tumors peaked in incidence before 3 years of age, with 61.8% of teratomas and 80% of yolk sac tumors occurring in this age group (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\n\u003ch3\u003eTumor Markers and Hormone Levels\u003c/h3\u003e\n\u003cp\u003eSerum α-fetoprotein (AFP) was elevated in 19 patients (95.0%) with yolk sac tumors and in 13 patients (19.1%) with teratomas (χ\u0026sup2; = 38.456, \u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001). The AFP level in yolk sac tumors (median, 3332.50 ng/mL; IQR, 489.86-4767.32 ng/mL) was significantly higher than in teratoma (median, 3.25 ng/mL; IQR, 1.35\u0026ndash;42.88 ng/mL) (U\u0026thinsp;=\u0026thinsp;79.5, \u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001). AFP levels were normal in all other tumor types except for a 22-month-old patient with mixed teratoma and yolk sac tumor (AFP\u0026thinsp;=\u0026thinsp;482.19 ng/mL) and a 2-month-old patient with juvenile granulosa cell tumor (AFP\u0026thinsp;=\u0026thinsp;244.19 ng/mL). Elevated preoperative testosterone levels were observed in 9 patients (7.6%), including 2 cases of Leydig cell tumor presenting with precocious puberty, 6 cases of teratoma, and 1 case of juvenile granulosa cell tumor. Preoperative β-human chorionic gonadotropin (β-hCG) levels were normal in all patients.\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eUS Manifestations and Pathology\u003c/h2\u003e \u003cp\u003eThe clinical, imaging, and pathological findings of testicular tumors in our study are summarized in Table\u0026nbsp;1 and demonstrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. The preoperative US maximum diameter of the lesion ranged from 0.5 to 7 cm (median, 1.9 cm; IQR, 1.1\u0026ndash;2.6 cm). Benign tumors (median, 1.4 cm; IQR, 0.9\u0026ndash;2.2 cm) were smaller than malignant tumors (median, 2.7 cm; IQR, 2.1\u0026ndash;3.6 cm) (U\u0026thinsp;=\u0026thinsp;79.5, \u003cem\u003eP\u003c/em\u003e\u0026lt; 0.001). Cystic lesions were present in 34 cases (28.8%), mixed solid-cystic lesions in 56 cases (47.5%), and solid lesions in 28 cases (23.7%) (Table\u0026nbsp;2). Tumors were predominantly well-circumscribed (91.5%).\u003c/p\u003e \u003cp\u003eCalcification was most commonly observed in teratomas (73.5%) and epidermoid cysts (46.7%), and also noted in 1 dermoid cyst, 1 yolk sac tumor, and 1 Sertoli-Leydig cell tumor. \u0026ldquo;Onion-ring\u0026rdquo; appearance was noted in 3 epidermoid cysts (25.5%), 2 dermoid cysts (50.0%), and 4 mature teratomas (6.5%). Hyperechoic rings were observed in 4 epidermoid cysts (33.3%) and 1 dermoid cyst (25.0%), arising from collagen-rich tissue creating an acoustic interface.\u003c/p\u003e \u003cp\u003eHomogeneous echogenicity with solid components was observed in 23/84 (27.4%) of non-pure cystic lesions, predominantly yolk sac tumors (n\u0026thinsp;=\u0026thinsp;15). Other homogeneous tumors included 1 mixed teratoma and yolk sac tumor, 1 Leydig cell tumor, 1 hemangioma, 1 rhabdomyosarcoma, and 4 secondary tumors. All purely cystic and 88.2% of cystic-dominant lesions were benign, including teratomas, epidermoid cysts, dermoid cysts, and juvenile granulosa cell tumors. Two cases of immature teratomas were exceptions, with predominantly cystic lesions. The PPV of cystic and cystic-dominant lesions for benign tumors was 96.1% (95% CI: 85.4\u0026ndash;99.3%), but the NPV was low (47.8%, 95% CI: 35.6\u0026ndash;60.2%). Most malignant tumors were solid or solid-dominant, with the exception of 5 cases of immature teratomas (2 predominantly cystic and 3 with equal proportions of solid and cystic components). The NPV of solid and solid-dominant lesions for malignancy was 91.5% (95% CI: 80.6\u0026ndash;96.8%), while the PPV was low (49.2%, 95% CI: 36.1\u0026ndash;62.4%). Combining this sonographic pattern (solid and solid-dominant) with AFP\u0026thinsp;\u0026gt;\u0026thinsp;300 ng/mL significantly improved diagnostic performance for yolk sac tumors (including mixed teratoma and yolk sac tumor): PPV 94.7% (95% CI: 71.9\u0026ndash;99.7%) and NPV 97.0% (95% CI: 90.8\u0026ndash;99.2%).\u003c/p\u003e \u003cp\u003eAll Leydig cell tumors (n\u0026thinsp;=\u0026thinsp;2), hemangiomas (n\u0026thinsp;=\u0026thinsp;2), and the Sertoli-Leydig cell tumor (n\u0026thinsp;=\u0026thinsp;1) were solid. Leydig cell tumors and hemangiomas in this cohort were relatively small, with all measuring less than 2 cm. Both Leydig cell tumors presented as ill-defined hypoechoic masses with a hyperechoic rim. Secondary tumors (n\u0026thinsp;=\u0026thinsp;4) uniformly presented as purely solid hypoechoic masses.\u003c/p\u003e \u003cp\u003eTwo rhabdomyosarcomas were identified. The first, an embryonal subtype, appeared as a homogeneous solid mass without cystic or calcified components and was initially misdiagnosed as a yolk sac tumor. The second, a spindle cell variant, presented as a large, predominantly solid lesion with heterogeneous echotexture, no calcification, and prominent vascularity. Additionally, a 10-month-old boy with seminoma had an ill-defined, hypoechoic intratesticular mass, characterized by heterogeneous echotexture and increased vascularity.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eDifferentiation between Teratoma and Yolk Sac Tumor\u003c/h2\u003e \u003cp\u003eWe specifically compared teratoma and yolk sac tumor as they represent the most common benign and malignant prepubertal testicular germ cell tumors, respectively. US characteristics of teratomas and yolk sac tumors are summarized in Table\u0026nbsp;3. Teratomas demonstrated a remarkably wide morphologic spectrum, with cases identified across all five sonographic classification categories: purely solid, purely cystic, and all three subcategories of mixed lesions (predominantly solid, balanced, and predominantly cystic) (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). Yolk sac tumors were significantly larger than teratomas (median 2.6 cm vs 1.6 cm, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and with a higher likelihood of solid architecture (60% vs 7.4%, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). They were predominantly homogeneous (75.0% vs 0.0%, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), hypervascular (100.0% vs 5.9%, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) with less frequent calcification (5.0% vs 73.5%, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). While all teratomas and most yolk sac tumors (85%) exhibited well-defined borders, yolk sac tumors more commonly exhibited poorly defined margins (15%), suggesting infiltrative growth or abnormal vascular supply, indicative of a more aggressive phenotype.\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eIt is evident that testicular tumors in childhood differ significantly from those in adolescence and adulthood, both in terms of incidence and histological characteristics, necessitating age-specific diagnostic frameworks. This retrospective cohort study establishes critical imaging-histology correlations that refine diagnostic pathways and guide management decisions for prepubertal testicular tumors.\u003c/p\u003e \u003cp\u003eIn our cohort, 71.8% of prepubertal tumors were benign, consistent with previous reports (74%) [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Cystic or cystic-dominant lesions demonstrated a near-perfect PPV for benignity (96.1%), predominantly mature teratomas and epidermoid cysts. This finding aligns with the European Society for Pediatric Urology (ESPU) guidelines, which recommend testis-sparing surgery for such lesions [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. In contrast, solid or solid-dominant masses exhibited a high NPV for malignancy (91.5%) but a low PPV (49.2%) due to the inclusion of benign entities such as mature teratomas, sex cord-stromal tumors, and hemangiomas.\u003c/p\u003e \u003cp\u003eEpidermoid and dermoid cysts, both originating from ectodermal elements, typically appear as well-defined, avascular masses. The classic \"onion-ring\" sign, characterized by concentric layers of alternating echogenicity, is highly suggestive of epidermoid cysts, though this feature is not always present and may occasionally be observed in teratomas. Hyperechoic ring is another key indicator of epidermoid cysts, though mixed echogenicity or calcification may complicate differentiation from teratomas. Prepubertal-type teratomas, not associated with Germ Cell Neoplasia In Situ (GCNIS), usually have an excellent prognosis with very low malignancy risk. As the most frequent pediatric testicular tumor, they demonstrate a remarkably wide morphologic spectrum, reflecting their composition of tissues from all three germ layers. The imaging features of mature and immature teratomas often overlap. Solid components appear more heterogeneous depending on the presence of different tissue types like cartilage, fibrous tissue, and adipose content. The cystic elements are not limited to the digestive or respiratory epithelia that produce mucus or digestive fluids (appearing as hypoechoic fluid with debris or a \"ground-glass\" echotexture), but may originate from various epithelium-lined structures derived from all three germ layers. For example, ectoderm-derived tissues like epidermis and choroid plexus may form keratin debris (manifesting as hyper-hypoechoic rings) or cerebrospinal fluid-like content (appearing as anechoic fluid). In rare cases, intra-abdominal testicular tumors could be suspected in infants presenting with abdominal mass/pain (potentially due to torsion) and undescended homolateral testis [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. While most intra-abdominal testicular tumors in prepubertal children are teratomas, exceptional cases of yolk sac tumor have been documented [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eYolk sac tumors are the most common malignant testicular germ-cell tumors in prepubertal children, with an incidence ranging from 8% to 30% [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Elevated serum AFP levels are present in 95\u0026ndash;98% of cases [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], typically exceeding 100 ng/mL [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. In our cohort, AFP was elevated in 95% of yolk sac tumors, with most values exceeding 300 ng/mL. US typically shows a large, round, or ovoid, solid, homogeneous mass that can completely occupy the affected testis, often with hypervascularity on color Doppler. Microcysts, identified in 40% of our yolk sac tumor cases, represented distinct histopathological structures rather than true epithelial-lined cysts and corresponded to regions of hemorrhagic necrosis.\u003c/p\u003e \u003cp\u003eLeydig cell tumors represent the most common sex cord-stromal tumors in children, followed by juvenile granulosa cell tumors. Leydig cell tumors typically occur between 5 and 10 years of age and present with precocious puberty secondary to excessive testosterone production. On US, they appear as isolated hypoechoic, hypervascular masses without calcification [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. In our series, both Leydig cell tumors demonstrated poorly defined margins with a hyperechoic rim, which can be attributed to their infiltrative, non-encapsulated growth pattern, that blends with seminiferous tubules. Differentiating Leydig cell tumors from testicular adrenal rest tumors (TARTs) is crucial, as both can present as hypoechoic masses with hormonal activity but require divergent management. TARTs typically present as bilateral peri-mediastinal lesions that may demonstrate a multilocular pattern without significant mass effect, with vascularity ranging from intense to minimal [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eJuvenile granulosa cell tumors are the most common congenital testicular tumors, typically occurring within the first 6 months of life and rarely diagnosed prenatally [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. These benign, hormonally inactive lesions rarely recur after testis-sparing surgery [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. On US, they characteristically present as well-encapsulated, multicystic masses with thick septations, resembling \"Swiss cheese\". These features correspond histologically to follicular structures containing basophilic or eosinophilic material, sometimes with hemorrhagic foci [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Color Doppler imaging demonstrates hypervascularity within solid components and septations [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. The early age of onset and normal or mildly elevated AFP levels (distinct from the marked elevation in yolk sac tumors) provide valuable diagnostic clues [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eLeukemia and lymphoma are the most common secondary testicular tumors in children. Among these, leukemia, particularly acute lymphoblastic leukemia (ALL), is the most prevalent. Testicular involvement is often a key indicator of relapse in these cases. US typically shows unilateral or bilateral testicular enlargement with homogeneous hypoechoic infiltration while preserving testicular contour. Color Doppler imaging reveals increased flow with a normal rectilinear course [\u003cspan additionalcitationids=\"CR21 CR22\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Histopathologically, these malignancies present as dense, monotonous sheets of small, round blue cells, resulting in uniform acoustic interfaces. These cells infiltrate the normal seminiferous tubules without forming distinct masses, while the blood vessel framework remains preserved.\u003c/p\u003e \u003cp\u003eThe bilateral testicular metastases observed in our cohort offer insights into neuroblastoma dissemination. To our knowledge, only a few similar cases have been documented. In this case, primary neuroblastomas appeared heterogeneous due to necrosis, calcification, and hemorrhage, whereas testicular metastases exhibited a homogeneous, hypoechoic appearance, a finding likely attributable to cellular selection during passage through blood-tissue barriers. Testicular hemangiomas are extremely rare and can mimic both benign and malignant lesions. In our study, two capillary hemangiomas appeared predominantly hypoechoic with tangled vascular channels, and color Doppler revealed marked intralesional hypervascularity. Unlike malignancies, which exhibit irregular and chaotic patterns, hemangiomas demonstrate organized vascular structures. Accurate preoperative diagnosis is essential to avoid unnecessary radical surgery. Paratesticular rhabdomyosarcoma accounts for 7% of all rhabdomyosarcomas, with a bimodal age distribution (peaks at 5 and 16 years) and a median diagnosis age of 7 years [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Embryonal rhabdomyosarcomas account for 90% of pediatric cases. In our cohort, the embryonal subtype presented as a homogeneous hypoechoic mass, mimicking the solid appearance of yolk sac tumors. These tumors are characterized by densely packed tumor cells with sparse stroma, resulting in homogeneous hypoechoic sonographic features. Normal AFP levels provide crucial diagnostic differentiation. In contrast, the spindle cell subtype manifested as a heterogeneous mass with microcysts, suggesting a myxoid extracellular matrix or ischemic necrosis.\u003c/p\u003e \u003cp\u003eWhile this study provides valuable insights into the clinical, pathological, and US features of pediatric testicular tumors, its retrospective design and single-center data limit generalizability. Future multicenter prospective studies with larger cohorts are needed to validate these findings. Further exploration of molecular markers and advanced imaging techniques, such as contrast-enhanced US [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], may enhance diagnostic accuracy and management.\u003c/p\u003e \u003cp\u003eIn conclusion, the integration of US and pathological analysis offers a comprehensive diagnostic framework for pediatric testicular tumors. Benign lesions are typically characterized by predominantly cystic components, well-defined borders, echogenic rims, or organized vascular patterns. Malignancy should be suspected when US shows solid-dominant masses with chaotic vascularity, particularly when accompanied by elevated AFP. Uncommon entities\u0026mdash;such as neuroblastoma metastases, hemangiomas, or paratesticular rhabdomyosarcoma\u0026mdash;though rare, exhibit distinctive sonographic and pathological features that help narrow the differential diagnosis.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eY.M. designed the study and wrote the main manuscript text. S.Y. , J.W. , L.L. , Y.W. , and H.R. collected clinical and imaging data. D.L. performed the pathological analysis. Y.M. and S.Y. performed the statistical analysis. All authors reviewed and approved the final manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003ePohl HG, Shukla AR, Metcalf PD, Cilento BG, Retik AB, Bagli DJ, Huff DS, Rushton HG (2004) Prepubertal testis tumors: actual prevalence rate of histological types. 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PMID: 29510439\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003e\u003cstrong\u003eTable 1: Clinical, US, and histopathological\u0026nbsp;characteristics of prepubertal testicular tumors\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"1011\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 107px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTumor histotype\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 47px;\"\u003e\n \u003cp\u003e\u003cstrong\u003en (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 86px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAge (month)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMaximum diameter (cm)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTumor markers and hormone levels\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 274px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eUS characteristics\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 299px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePathological correlation\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 107px;\"\u003e\n \u003cp\u003eEpidermoid cyst and Dermoid cyst\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e16 (13.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 86px;\"\u003e\n \u003cp\u003eMedian, 76.5;\u003cbr\u003e\u0026nbsp; IQR, 28.0-76.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 93px;\"\u003e\n \u003cp\u003eMedian, 0.9; IQR, 0.6-1.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003eUsually without hormonal activity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 274px;\"\u003e\n \u003cp\u003eWell-defined, round or oval avascular lesion.\u003cbr\u003e\u0026nbsp;\u0026quot;Onion-ring\u0026quot; appearance of multiple concentric layers of alternating echogenicity.\u003cbr\u003e\u0026nbsp;May have a hyperechoic ring.\u003cbr\u003e\u0026nbsp;Well-demarcated mixed echogenic lesion with or without calcifications.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 299px;\"\u003e\n \u003cp\u003eKeratin-producing epithelium is responsible for the keratin accumulation within the lumen of the cyst that appears hyperechoic on US. Dermoid cysts differ from epidermoid cysts in that they contain skin appendages, such as hair follicles and sebaceous glands.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 107px;\"\u003e\n \u003cp\u003eTeratoma, prepubertal type\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e68 (57.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 86px;\"\u003e\n \u003cp\u003ePeak incidence before 3 years of age\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 93px;\"\u003e\n \u003cp\u003eMedian, 1.6; IQR, 1.1-2.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003eAFP: may be mildly elevated\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 274px;\"\u003e\n \u003cp\u003eWide spectrum: Ranging from predominantly cystic to predominantly solid lesions, though most demonstrate mixed solid-cystic architecture.\u003cbr\u003e\u0026nbsp;Calcification is common.\u003cbr\u003e\u0026nbsp;Well-defined margins.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 299px;\"\u003e\n \u003cp\u003eThe relative proportions of cystic elements (e.g., serous or mucinous fluid), solid tissues (e.g., mesenchymal stroma, glial tissue), and calcifications directly influence their echogenic properties, leading to a spectrum of echogenic patterns ranging from anechoic cysts to complex, heterogeneous masses.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 107px;\"\u003e\n \u003cp\u003eYolk sac tumor, prepubertal type\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e20 (16.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 86px;\"\u003e\n \u003cp\u003ePeak incidence before 3 years of age\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 93px;\"\u003e\n \u003cp\u003eMedian, 2.6; IQR, 2.0-3.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003eAFP: markedly elevated\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 274px;\"\u003e\n \u003cp\u003eOvoid, homogeneous solid lesion with isoechoic to hypoechoic echotexture.\u003cbr\u003e\u0026nbsp;Prominent hypervascularity.\u003cbr\u003e\u0026nbsp;Microcysts may be present, but conspicuous cystic areas are usually absent unless the tumor is larger.\u0026nbsp;\u003cbr\u003e\u0026nbsp;Calcification seldom occers.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 299px;\"\u003e\n \u003cp\u003eThe uniformity of the US features correlates with the dense cellular architecture of the tumor at the histological level.\u003cbr\u003e\u0026nbsp;Lack significant fluid or cystic components, although occasional evident hemorrhage or necrosis may be present.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 107px;\"\u003e\n \u003cp\u003eLeydig cell tumor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e2 (1.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 86px;\"\u003e\n \u003cp\u003e58; 68\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003e1.3; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003eTypically with levated testosterone\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 274px;\"\u003e\n \u003cp\u003ePresents as a small, solid, hypoechoic mass.\u003cbr\u003e\u0026nbsp;May demonstrate ill-defined margins with a peripheral hyperechoic rim.\u003cbr\u003e\u0026nbsp;Color Doppler imaging reveals intralesional hypervascularity.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 299px;\"\u003e\n \u003cp\u003eTumors lack a true fibrous capsule, with tumor cells infiltrating between seminiferous tubules and blending with the normal parenchyma.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 107px;\"\u003e\n \u003cp\u003eJuvenile granulosa cell tumor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e1 (0.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 86px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003e3.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003eUsually without hormonal activity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 274px;\"\u003e\n \u003cp\u003e\u0026quot;Swiss cheese\u0026quot; multilocular pattern mass.\u003cbr\u003e\u0026nbsp;Solid components are typically hypoechoic or isoechoic and demonstrate increased vascularity.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 299px;\"\u003e\n \u003cp\u003eTumors are characterized by multiple cystic spaces, formed by fluid accumulation from neoplastic granulosa cells. These cysts are usually lined with granulosa cells and may include areas of hemorrhage or necrosis.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 107px;\"\u003e\n \u003cp\u003eHemangioma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e2 (1.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 86px;\"\u003e\n \u003cp\u003e81; 112\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003e1.9; 0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003eUsually without hormonal activity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 274px;\"\u003e\n \u003cp\u003ePredominantly hypoechoic masses demonstrating prominent, organized intralesional hypervascularity.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 299px;\"\u003e\n \u003cp\u003eHemangiomas are composed of clusters of blood vessels, which form a tangled network of vascular channels.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 107px;\"\u003e\n \u003cp\u003eSecondary tumor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e4 (3.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 86px;\"\u003e\n \u003cp\u003e7; 85; 89; 127\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003e3.5; 3.6; 2.5; 4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003eUsually without hormonal activity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 274px;\"\u003e\n \u003cp\u003eUnilateral or bilateral.\u003cbr\u003e\u0026nbsp;Testes present a big size with diffuse or focal homogeneous hypoechoic infiltration.\u003cbr\u003e\u0026nbsp;Preserved testicular shape.\u003cbr\u003e\u0026nbsp;Usually hypervascular while maintaining normal vascular course and branching patterns.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 299px;\"\u003e\n \u003cp\u003eDiffuse infiltration of monotonous sheets of small, round blue cells results in a homogeneous tissue architecture, creating uniform acoustic interfaces on US.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eAFP, alpha-fetoprotein.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2. Distribution of tumor histotypes according to US classification of tumor components\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"641\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 240px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eClassification of tumor components\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTumor histotype\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e\u003cstrong\u003en (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 240px;\"\u003e\n \u003cp\u003eCystic\u003cbr\u003e\u0026nbsp;34 (28.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eMature teratoma, prepubertal type\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e18 (52.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eEpidermoid cyst\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e12 (35.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eDermoid cyst\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e4 (11.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 240px;\"\u003e\n \u003cp\u003ePredominantly cystic\u003cbr\u003e\u0026nbsp;17 (14.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eMature teratoma, prepubertal type\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e14 (82.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eImmature teratomas, prepubertal type\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e2 (11.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eJuvenile granulosa cell tumor\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e1 (5.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 240px;\"\u003e\n \u003cp\u003eEqual proportion of solid and cystic components\u003cbr\u003e\u0026nbsp;8 (6.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eMature teratoma, prepubertal type\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e5 (62.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eImmature teratomas, prepubertal type\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e3 (37.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"5\" style=\"width: 240px;\"\u003e\n \u003cp\u003e\u0026nbsp;Predominantly solid\u003cbr\u003e\u0026nbsp;31 (26.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eMature teratoma, prepubertal type\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e20 (64.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eYolk sac tumor, prepubertal type\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e8 (25.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eImmature teratomas, prepubertal type\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e1 (3.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eRhabdomyosarcoma\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e1 (3.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eMixed teratoma and yolk sac tumor, prepubertal type\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e1 (3.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"8\" style=\"width: 240px;\"\u003e\n \u003cp\u003eSolid\u003cbr\u003e\u0026nbsp;28 (23.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eYolk sac tumor, prepubertal type\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e12 (42.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eMature teratoma, prepubertal type\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e5 (17.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eSecondary tumor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e4 (14.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eLeydig cell tumor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e2 (7.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eHemangioma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e2 (7.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eSeminoma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e1 (3.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eSertoli-Leydig cell tumor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e1 (3.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 333px;\"\u003e\n \u003cp\u003eRhabdomyosarcoma\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 68px;\"\u003e\n \u003cp\u003e1 (3.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3: US features of prepubertal teratoma and yolk sac tumor\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"900\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 266px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eParameters\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 222px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTeratoma, prepubertal type\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 227px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eYolk sac tumor, prepubertal type\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 84px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eStatistic\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003eP value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003eMaximum diameter (cm), median (IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e1.6 (1.1, 2.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e2.6 (2.0, 3.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003eU=364.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003eLaterality\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026chi;2=0.549\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e0.459\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003eRight (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e31/68 (45.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e11/20 (55.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003eLeft (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e37/68 (54.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e9/20 (45.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003eTumor components\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026chi;2=23.63\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e＜0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003eCystic (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e18/68 (26.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e0/20 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003ePredominantly cystic (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e16/68 (23.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e0/20 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003eEqual proportion of solid and cystic components (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e8/68 (11.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e0/20 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003e\u0026nbsp;Predominantly solid (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e21/68 (30.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e8/20 (40.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003eSolid (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e5/68 (7.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e12/20 (60.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003eBorder\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003eWell-defined\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e68/68 (100.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e17/20 (85.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003ePoorly defined\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e0/68 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e3/20 (15.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 266px;\"\u003e\n \u003cp\u003eHomogeneity of solid components\u003cbr\u003e\u0026nbsp;(Teratoma, n=50; Yolk sac tumor, n=20)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026chi;2=43.38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e＜0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003eHomogeneous\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e0/50 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e15/20 (75.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003eHeterogeneous\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e50/50 (100.00)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e5/20 (25.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003eCalcification (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e50/68 (73.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e1/20 (5.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026chi;2=29.79\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e＜0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003eVascularity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026chi;2=69.02\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e＜0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003eGrade 0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e43/68 (63.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e0/20 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003eGrade 1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e18/68 (26.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e0/20 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003eGrade 2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e3/68 (4.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e0/20 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 266px;\"\u003e\n \u003cp\u003eGrade 3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 222px;\"\u003e\n \u003cp\u003e4/68 (5.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 227px;\"\u003e\n \u003cp\u003e20/20 (100.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 101px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"pediatric-radiology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"prad","sideBox":"Learn more about [Pediatric Radiology](http://link.springer.com/journal/247)","snPcode":"247","submissionUrl":"https://submission.nature.com/new-submission/247/3","title":"Pediatric Radiology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"child, testicular tumor, ultrasound, imaging","lastPublishedDoi":"10.21203/rs.3.rs-9115875/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9115875/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e Prepubertal testicular tumors represent a distinct clinicopathologic spectrum that differs significantly from adult testicular tumors, necessitating age-specific diagnostic strategies to guide management and preserve testicular function. Purpose This study aimed to characterize the ultrasound (US) features of various histological subtypes of prepubertal testicular tumors and correlate these findings with histopathological results to provide diagnostic clues.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaterials and Methods\u003c/strong\u003e This retrospective study analyzed consecutive pediatric patients with pathologically confirmed testicular tumors at our institution between November 2016 and June 2024. All patients underwent preoperative scrotal US evaluating multiple parameters including tumor size, composition (solid, cystic, mixed), echotexture, vascularity, and calcification. Pathological diagnosis served as the reference standard. Lesions were systematically assessed by correlating US features, such as hyperechoic rings and vascular patterns, with corresponding histological sections.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e The cohort included 118 lesions, with a peak incidence within the first 3 years of life. Benign tumors (e.g., teratoma, epidermoid cyst) constituted 71.2% of cases. A cystic or cystic-dominant US pattern demonstrated a high positive predictive value (PPV) of 96.1% for benignity, but low negative predictive value (NPV) of 47.8%. In contrast, solid or solid-dominant masses exhibited a high NPV for malignancy (91.5%) but a low PPV (49.2%), due to the inclusion of benign entities such as mature teratomas, sex cord-stromal tumors, and hemangiomas. Combining this sonographic pattern (solid and solid-dominant) with AFP \u0026gt;300 ng/mL significantly improved diagnostic performance for yolk sac tumors: PPV 94.7% (95% CI: 71.9–99.7%) and NPV 97.0% (95% CI: 90.8–99.2%). Uncommon entities like juvenile granulosa cell tumors exhibited pathognomonic \"swiss-cheese\" morphology, while Leydig cell tumors demonstrated infiltrative margins attributed to their unique histopathological growth patterns. Rare metastases and rhabdomyosarcomas presented with distinguishing features that, when combined with clinical context, facilitated\u0026nbsp;accurate diagnosis.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion \u003c/strong\u003eThe combination of high-resolution US and pathological analysis provides a powerful diagnostic framework for prepubertal testicular tumors. Specific US patterns correlate with histologic subtypes and malignant potential. This integrated approach is essential for risk stratification, guiding surgical decisions, and preventing the mismanagement of rare tumor types.\u003c/p\u003e","manuscriptTitle":"Prepubertal Testicular Tumors in Children: Combined Ultrasound and Pathologic Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-25 17:15:32","doi":"10.21203/rs.3.rs-9115875/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-05-10T19:14:16+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"69096505384502935147000433566513587568","date":"2026-05-02T20:45:41+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-13T10:19:36+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"175449800098177616713454735522094576884","date":"2026-03-26T15:06:32+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-03-23T04:22:22+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-03-16T04:25:21+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-03-16T04:25:08+00:00","index":"","fulltext":""},{"type":"submitted","content":"Pediatric Radiology","date":"2026-03-13T14:32:41+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"pediatric-radiology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"prad","sideBox":"Learn more about [Pediatric Radiology](http://link.springer.com/journal/247)","snPcode":"247","submissionUrl":"https://submission.nature.com/new-submission/247/3","title":"Pediatric Radiology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"9c2b3c4d-f334-4a3b-b8c0-38f360bbeda6","owner":[],"postedDate":"March 25th, 2026","published":true,"recentEditorialEvents":[{"type":"editorInvitedReview","content":"","date":"2026-05-10T19:14:16+00:00","index":31,"fulltext":""},{"type":"reviewerAgreed","content":"69096505384502935147000433566513587568","date":"2026-05-02T20:45:41+00:00","index":30,"fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-03-25T17:15:32+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-25 17:15:32","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9115875","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9115875","identity":"rs-9115875","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}