Giant Serous Cystadenoma Masquerading as Ascites in an Adolescent by Ultrasound: A Case Report and Review of Diagnostic Challenges

Giant Serous Cystadenoma Masquerading as Ascites in an Adolescent by Ultrasound: A Case Report and Review of Diagnostic Challenges | 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 Case Report Giant Serous Cystadenoma Masquerading as Ascites in an Adolescent by Ultrasound: A Case Report and Review of Diagnostic Challenges EMMANUEL ADEYEMI ODUMERU, Adam Afodun, Costelia Njoku, Theresa Anele This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7735568/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Giant ovarian serous cystadenomas are uncommon in adolescents and present much like ascites, which may cause diagnostic delays and mistreatment. Correct imaging and laboratory workup are essential to allow treatment in time with the preservation of fertility. Case Presentation A 16-year-old girl was referred from the pediatric unit to the ultrasound unit of the teaching hospital in the southeast of Nigeria, with the symptoms of progressive abdominal distension, pain, a history of continuous vaginal bleeding and anemia. The initial ultrasound had indicated free peritoneal fluid. A large cystic mass almost filling the abdomen was seen on extended-field-of-view (EFOV) imaging. Laboratory results showed iron deficiency anemia and hormonal derangement. Surgical exploration revealed a 4.25 kg serous cystadenoma derived from the right ovary. A study of histopathology proved an origin from benign epithelium. Our case emphasizes that EFOV is valuable in distinguishing large cystic masses from ascites despite the predominantly bilobar mass and characteristic cut-off appearance, especially in environments with limited resources when used alongside laboratory workup and histology for management. Conclusion Giant serous cystadenomas, although rare in adolescence, should be kept in mind when adolescents present with unexplained abdominal enlargement. High level of attention to sonographic skill and vigilance in the clinic is crucial for resemble diagnosis and the best outcome. Nuclear Medicine & Medical Imaging Surgical Obstetrics & Gynecology Pediatrics Serous cystadenoma adolescent ascites ultrasound Laboratory investigations histology Figures Figure 1 Figure 2 Figure 3 1.0 Introduction It is rare for children to get ovarian tumors, and about 2.65 cases occur each year in 110,000 girls. [ 1 ] Such epithelial ovarian tumors, regardless of type, are uncommon in children and adolescents. In fact, serous cystadenoma accounts for only 10–20% of ovarian neoplasms in this age group. [ 2 ] Although pediatric ovarian tumors are mostly of germ cell origin, the incidence of epithelial tumors increases in late adolescence and early adulthood. The clinical presentation is characterized by a distended abdomen, pain, and menstrual irregularities. Ectopic fat in the peritoneum may simulate ascites ultrasonically, and large cystic masses are necessary to cause diagnostic confusion. [ 3 ] Transabdominal sonography (TAS) is often the first imaging method used. However, if further accuracy is needed, Extended Field of View (EFOV) combined with high-frequency probes can be helpful, especially when larger lesions are present. One step further still is Magnetic Resonance Imaging (MRI) for its superb resolution in depicting subtle tissue differences, or Computerized Tomography (CT) scans when ultrasound evaluation stalls. [ 4 ] Preoperative laboratory work-up is important as it enables the surgeon not only to exclude malignancy but also to provide significant guidance for planning. Tumor markers like CA-125, AFP, β-hCG, and LDH help in distinguishing benign from malignant ovarian masses; hematological parameters can indicate chronic blood loss, as with large tumors or systemic effects of pressure on the circulation. Endocrine disruption can be revealed by hormonal assays due to the mass effect upon ovarian function. [ 5 , 6 ] Dependence on histological examination for definitive diagnosis remains paramount. It confirms the benign nature of cystadenomas, dismisses atypia or borderline features, and informs postoperative management with regard to prognosis. [ 7 ] For adolescents, fertility-sparing surgery is prioritized, and histology ensures oncologic safety without compromise of reproductive potential. [ 7 ] This report records a rare case of giant serous cystadenoma in an adolescent, highlighting its imaging strategies, laboratory support and histopathological certification to guide timely, effective management. 2.0 Case Presentation A sixteen-year-old girl presented to the pediatric outpatient clinic with a three-month history of gradually increasing abdominal girth and intermittent lower abdominal discomfort. She had no history of fever, weight loss, flushing of the face, doubling over in pain, intermittent loose stools, or menstrual irregularities. Initial clinical assessment suggested ascites, and the patient was referred for laboratory investigations, abdomino-pelvic ultrasound and histopathology. 2.1 Table 1: Laboratory Investigation Results Test Expected Value Reference Range Haemoglobin (Hb) 6.4 g/dL 12.0–16.0 g/dL Hematocrit (Hct) 24% 35–47% RBC Count 2.8 ×10⁶/µL 4.2–5.5 ×10⁶/µL Platelets 520 ×10³/µL 155–400 ×10³/µL Serum Ferritin 12.6 ng/mL 15–155 ng/mL Serum Iron 29 µg/dL 50–175 µg/dL TIBC 460 µg/dL 240–410 µg/dL MCV 65 fL 75–95 fL Transferrin Saturation 7.0% 15–45% WBC Count 7.9 ×10³/µL 4.6–11 ×10³/µL CA-125 30 U/mL <35.5 U/mL PT/INR Within normal limits PT: 10–13.6 sec, INR: 0.78–1.26 Estradiol 65 pg/mL 14–62 pg/mL (follicular phase) FSH/LH Suppressed Age-dependent AFP, β-hCG, LDH Within normal limits Age-dependent 2.2 Ultrasound Findings (Conventional and Extended Field-of-View Imaging) An initial conventional ultrasound was undertaken using a 3MHz curvilinear transducer. Technically, it was very difficult to remove all the anechoic fluid, and an attempt was made in this direction. However, this simply led us to another problem: the large quantities of highly reflective solid matter situated within were suddenly identified as being of pathological significance. On top of that, because bowel loops were compressed wherever they touched the liquid-based contents, their shapes and positions actually changed with each breath taken. There was no internal septation or solid component within the fluid. The uterus was displaced posteriorly. EFOV ultrasound was then used to further clarify the dimensions and nature of the mass; it was achieved using a 5 MHz curvilinear probe for more profound pelvic visualization and a 10 MHz linear transducer with greater resolution for the structure of fluid and its boundaries. This overall view revealed that a large, complex cystic mass with thin internal septa extended over a substantial portion of the abdominal cavity. No solid mural nodules were detected. Ovarian structures were visualized, probably already in a state of mass effect, located beyond the scan field. The uterus or bladder seemed to be in more or less normal shapes and positions. It is noteworthy that the right renal calyces showed better than usual dilation, and after moving bowel loops leftwards, there was a mild downward dip from the center of your screen. No peritoneal fluid was observed. 2.3 Surgical Intervention Following a clinical presentation of progressive abdominal distension, intermittent bleeding per vagina, lab and imaging findings, the patient underwent an exploratory laparotomy under general anaesthesia. Discovery of a markedly distended abdomen with an enormous pelvic mass extending above the level of the umbilicus was described in the preoperative evaluation. Two units of packed red blood cells were transfused perioperatively. Intraoperatively, a giant multilocular cystic mass was identified protruding from the right ovary. The uterus and left adnexa were grossly normal, with no hint of ascites. I performed a right oophorectomy; the excised mass weighed 4250 grams, consistent with a giant serous cystadenoma. A specimen of the mass was submitted to the histopathology unit for confirmation. The procedure was completed without incident, and the patient was transferred to the recovery room in stable condition. 2.4 Post-Operative The postoperative recovery was uneventful, with cessation of bleeding from VI months on, and improvement in hematologic parameters returning to normal within two weeks. 2.5 Histopathology Histologically, the micrographs showed a cyst lined by columnar epithelium, with or without atypia, regardless of the presence or absence of evidence of malignancy. No papillary projections or stromal invasion were seen. The final diagnosis was "benign serosal cystadenoma." 3.0 Discussion The patient reported in this case study is a teenager. She came to the hospital with abdominal distention, which, in the beginning, was thought to be ascites. However, after diagnosis, which included enhanced ultrasound imaging techniques, laboratory and histologic investigations, a surgical intervention provided a good correlation to the diagnosis and a successful outcome. 3.1 Laboratory Measurements In the present case, the laboratory results for the teenager showed microcytic hypochromic anemia and iron loss; these are most likely due to chronic vaginal bleeding and Iron Deficiency Anemia (IDA). Iron Deficiency Anemia remains fairly common in adolescent girls, with prevalence estimates of 17–33% worldwide. [ 8 ] Endometrial compression and hormonal imbalance (due to mass effect) are believed to be causing persistent vaginal bleeding, which significantly impairs haemodynamic stability and oxygen-carrying capacity. [ 6 ] The raised platelet count indicates reactive thrombocytosis, a common finding in iron deficiency and inflammatory conditions. Mildly elevated CA-125 (45U/mL) may indicate peritoneal irritation rather than malignancy. Benign cysts can produce CA-125 but do not necessarily form tumors. [ 5 ] The elevated estradiol (85pg/mL) along with suppressed gonadotrophins suggests a disturbance. Although serous cystadenomas are typically non-functional, large ovarian masses (even in the absence of hormone-secreting endometrial cells) can lead to impairment in feedback control. [ 6 ] Present findings are a reflection of the amount of tumor burden, chronic bleeding, and endocrine modulation brought about by tumors. 4.2 Ultrasound Imaging and Challenges The formal invention of Extended Field of View (EFOV) ultrasound was for the purpose of showing the full extent of a mass in a structure, especially considering that the size is large and its anatomical displacement. EFOV imaging not only gives a greater spatial context but also aids in showing the mass in its long axis and short axis with good characterization. [ 4 ] With the widespread use of this technology, it has also been found ideal for evaluating large pelvic masses which exceed the ordinary transducer field of view. High-frequency transducers, such as those used with 10 MHz, produce better resolution of internal septations and wall features than the lower-frequency transducers of 3.0 MHz. For these transducers, axial resolution is better than before, and that is important: it means that more subtle structures like thin septa or nodular muscles can be detected. The rapid growth of a cystadenoma likely results from epithelial cell proliferation and fluid accumulation in branching tubules, which are characteristic of benign serous tumors. [ 7 ] These can also occur in malignant tumors during transformation to a degree that is worthy of note, for example. Although malignant transformation is rare in teenagers, it should be accounted for in the differential diagnosis. Ultrasound appearance cannot confidently predict malignancy because its sensitivity is limited, and the false negatives have not yet been addressed. [ 6 ] Additional modalities like shear wave elastography show promise in differentiating benign from malignant ovarian lesions by assessing tissue stiffness. Recent studies draw a direct correlation between elastographic scores, Doppler results and tumor markers of CA-125 and HE4. [ 9 ] It's difficult to diagnose giant ovarian cysts, especially serous ones, with ultrasound, especially when they are mistaken for ascites. [ 10 ] Frequently, the most serious diagnostic error is to confuse large, anechoic cysts with free ascitic fluid. [ 3 , 10 ] Teenagers are of little practical reference in this respect because they rarely have ascites themselves. [ 1 , 2 ] This can delay the necessary surgical intervention. Furthermore, difficulty visualizing cyst walls and displaced ovaries complicates evaluation. [ 9 ] Recent research indicates that even experienced sonographers may miss giant cystadenomas occupying the entire abdomen. [ 4 , 6 , 9 ] Massive distension also interferes with ultrasound imaging. Multiple studies have pointed out that in areas where CT or MRI are lacking, reliance on ultrasound alone creates diagnostic dilemmas and brings clinical hazards. [ 10 ] When the ovary is compressed or unseen parenchymal origin is difficult to determine, Doppler ultrasound can help detect vascular pedicles, but it becomes less effective as the cyst gets larger and its discomfort in patients further increases. Intestinal gas shadows can hide key features such as septa or mural nodules, making it more difficult to determine malignancy. [ 4 , 6 , 9 , 10 ] Though ultrasound remains a valuable tool for initial evaluation, the findings must be critically analyzed. Techniques such as EFOV, patient repositioning and additional imaging methods can improve accuracy, reduce the chance of misdiagnosis. However, histopathological analysis after biopsy or surgical excision is the definitive method for diagnosis and risk assessment. Conclusion Although giant serous cystadenomas are rare in adolescents, they should be considered in the differential diagnosis of unexplained abdominal distension. Accurate identification relies on EFOV ultrasound with high-frequency probes; additional investigation with special tests specific to explaining appearance characteristics may play an important role in excluding a malignant tumor. Definitive diagnosis that confirms a benign nature is obtained through histopathological examination, and this guides surgical intervention tailored to the patient's age and desire for future fertility. A combined approach integrating imaging, laboratory data, and histology ensures timely management and successful outcomes for young patients. Abbreviations Transabdominal sonography (TAS) Extended Field of View (EFOV) Magnetic Resonance Imaging (MRI) Computerized Tomography (CT) Alpha-Fetoprotein (AFP) Beta-Human Chorionic Gonadotropin (β-hCG) Lactate Dehydrogenase (LDH) Iron Deficiency Anemia (IDA) Megahertz (MHz) Declarations Ethics approval and consent to participate In terms of the Declaration of Helsinki, this study was initiated with formal approval from the hospital's ethics committee. Consent for publication Each parent, on behalf of the adolescent patient, signed an informed consent form before the beginning of our data collection process for publication. Availability of data and materials The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request. Competing interests The authors declare that they have no competing interests Funding The authors received no funds for this study Authors' contributions OE performed the diagnostic ultrasound, and both OE and AT analyzed and interpreted the patient data regarding the patient's condition and surgery. CN performed the laboratory and histological examinations of the patient and the Ovarian mass. All the authors are contributors to the writing of the manuscript. All authors read and approved the final manuscript. Acknowledgements We acknowledge the staff of the Radiology department of FMC Teaching Hospital for their assistance in making the collection of the patient’s data possible. References Bašković M, Habek D, Zaninović L et al (2025) The evaluation, diagnosis, and management of ovarian cysts in pediatric populations. Healthcare 13(7):775 Krauel L, Pasten A (2024) Ovarian tumours in children and adolescents. Survival Handbook in Pediatric Surgical Oncology. Springer, pp 93–97 Pocha C, Rios-Perez C (2025) Ascites, the Old, the Current, and the Future Ways of Management. Curr Hepatol Rep 24(19). https://doi.org/10.1007/s11901-025-00690-x Hussain S, Mubeen I, Ullah N, Shah SSUD, Khan BA, Zahoor M, Ullah R, Khan FA, Sultan MA (2022) Modern Diagnostic Imaging Technique Applications and Risk Factors in the Medical Field: A Review. Biomed Res Int 2022:5164970. 10.1155/2022/5164970 PMID: 35707373; PMCID: PMC9192206 Sharma D, Vinocha A (2020) Benign Ovarian Cysts with Raised CA-125 Levels: Do We Need to Evaluate the Fallopian Tubes? J Lab Physicians 12(04):276–280. 10.1055/s-0040-1722547 Jin C, Deng M, Bei Y, Zhang C, Wang S, Yang S, Qiu L, Liu X, Chen Q (2024) The predictive value of nomogram for adnexal cystic-solid masses based on O-RADS US, clinical and laboratory indicators. BMC Med Imaging 24(1):315. 10.1186/s12880-024-01497-w PMID: 39558247; PMCID: PMC11575063 Ross CJ, Hanley (2024) Krisztina Ovary Serous tumours: Serous cystadenoma, adenofibroma and surface papilloma PathologyOutlines.com. Inc ; 130(38) Weyand AC, Chaitoff A, Freed GL, Sholzberg M, Choi SW, McGann PT (2023) Prevalence of Iron Deficiency and Iron-Deficiency Anaemia in US Females Aged 12–21 Years, 2003–2020. JAMA. ; 329(24): 2191–2193. doi: 10.1001/jama. 2023.8020. PMID: 37367984; PMCID: PMC10300696 Hanafy MM, Rafaat M, Ibrahem HM, Atta FMM, Hashem LMB (2025) Can transabdominal shear wave elastography play a role in solving the dilemma of complex cystic and solid ovarian tumours by ultrasound? J Ultrasound. May 31. 10.1007/s40477-025-01027-6 . Epub ahead of print. PMID: 40448793 Kamabu LK, Mulisya O, Butala ES (2023) Challenges associated with delayed diagnosis of a giant ovarian mucinous cystadenoma in low-resourced settings: a case report. MOJ Clin Med Case Rep 13(2):e00430. https://medcraveonline.com/MOJCR/MOJCR-13-00430.pdf Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted 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-7735568","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":521804393,"identity":"8d0eac3e-4061-4e93-b3ff-33da049ee0fe","order_by":0,"name":"EMMANUEL ADEYEMI ODUMERU","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA8ElEQVRIiWNgGAWjYJCCAwxscLYNA4MEaVoS0ojTwoCk5TBhLQbHuxMPfCg7LM8v3fzwceGP84n9s5sPPmCosYnGqeXM2Q0HZ5w7bDhzzjFj4xkJtxNn3DmWbMBwLC23AZeWG7kbDvO2HU4wuJHDJs0D1NJwI8dMgrHhMG4t99/CtbD/5kk4lzifoJYbvAhbmHkSDiRuIKRF8kwuyC/phjNnpBlLz0hLNt54Iy3ZIAGPX/iOn9384UOZtTy/RPLDzwU2drLzbiQffPChxganFoUDSBxmIHYEq0zAoRwE5JHNAmmxx6N4FIyCUTAKRigAAMilZWm3aTBdAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0002-5841-9061","institution":"UNIVERSITY OF RWANDA","correspondingAuthor":true,"prefix":"","firstName":"EMMANUEL","middleName":"ADEYEMI","lastName":"ODUMERU","suffix":""},{"id":521804394,"identity":"5851cc96-4756-4d62-9c6e-0688f132ed18","order_by":1,"name":"Adam Afodun","email":"","orcid":"","institution":"UNIVERSITY OF RWANDA","correspondingAuthor":false,"prefix":"","firstName":"Adam","middleName":"","lastName":"Afodun","suffix":""},{"id":521804395,"identity":"dad852af-ff82-471e-b035-ad6b303a79ac","order_by":2,"name":"Costelia Njoku","email":"","orcid":"","institution":"Mount Kenya University","correspondingAuthor":false,"prefix":"","firstName":"Costelia","middleName":"","lastName":"Njoku","suffix":""},{"id":521804396,"identity":"0edce373-d717-49f9-a8d9-b4f8d77f5d21","order_by":3,"name":"Theresa Anele","email":"","orcid":"","institution":"Federal Medical teaching Hospital, Owerri","correspondingAuthor":false,"prefix":"","firstName":"Theresa","middleName":"","lastName":"Anele","suffix":""}],"badges":[],"createdAt":"2025-09-28 16:16:36","currentVersionCode":1,"declarations":{"humanSubjects":true,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":true,"humanSubjectConsent":true,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":true,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-7735568/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7735568/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":92480625,"identity":"5bff9e8b-945e-4d65-849e-818902a2a3c3","added_by":"auto","created_at":"2025-09-30 07:41:52","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1545027,"visible":true,"origin":"","legend":"","description":"","filename":"RevisedCystadenomamanuscriptforResearchSquare.docx","url":"https://assets-eu.researchsquare.com/files/rs-7735568/v1/956a2de233c798661c01fa0a.docx"},{"id":92480619,"identity":"392282ed-57fa-4781-be4d-69de66b88fee","added_by":"auto","created_at":"2025-09-30 07:41:51","extension":"json","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":342,"visible":true,"origin":"","legend":"","description":"","filename":"rs7735568.json","url":"https://assets-eu.researchsquare.com/files/rs-7735568/v1/e7da95defd9ab383b70d9755.json"},{"id":92480622,"identity":"453489ff-d411-494d-8a53-e773ce75813f","added_by":"auto","created_at":"2025-09-30 07:41:51","extension":"xml","order_by":2,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":45806,"visible":true,"origin":"","legend":"","description":"","filename":"rs77355680enriched.xml","url":"https://assets-eu.researchsquare.com/files/rs-7735568/v1/a67f2392daef39300a5408be.xml"},{"id":92480626,"identity":"a78c84ff-2d18-40a8-840f-cec6d09bb85f","added_by":"auto","created_at":"2025-09-30 07:41:52","extension":"emf","order_by":3,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":2400048,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage1.emf","url":"https://assets-eu.researchsquare.com/files/rs-7735568/v1/3875d126a4c947aac521dc63.emf"},{"id":92480624,"identity":"8f44eb0d-3a5f-4a71-b9ec-dc1885b81ebc","added_by":"auto","created_at":"2025-09-30 07:41:52","extension":"png","order_by":4,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":236157,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7735568/v1/27078da35e77acf7852212a7.png"},{"id":92480632,"identity":"4d1e43b0-2dc2-4efc-a9d9-2510bc276db9","added_by":"auto","created_at":"2025-09-30 07:41:52","extension":"png","order_by":5,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":397180,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-7735568/v1/e16f867e90adc8b1a3d29e50.png"},{"id":92480631,"identity":"ffa45459-eb90-4f3a-a0f0-0055fb9ef0aa","added_by":"auto","created_at":"2025-09-30 07:41:52","extension":"png","order_by":6,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":53085,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7735568/v1/3f55b8e0c6e2e94809e5bc22.png"},{"id":92480628,"identity":"6e41b5f8-b45e-4098-b89e-c2478cf18a34","added_by":"auto","created_at":"2025-09-30 07:41:52","extension":"png","order_by":7,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":20853,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7735568/v1/13f24a0f0d5d5d037f1c5dbf.png"},{"id":92481294,"identity":"56140341-cd60-49e2-a2c3-d568fe2dfde3","added_by":"auto","created_at":"2025-09-30 07:49:52","extension":"png","order_by":8,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":46016,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-7735568/v1/3e3b7b6751b5d1b9636b0be3.png"},{"id":92482675,"identity":"d20954e5-9e36-4d5b-bd52-4ac8812f6a8d","added_by":"auto","created_at":"2025-09-30 07:57:52","extension":"xml","order_by":9,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":43867,"visible":true,"origin":"","legend":"","description":"","filename":"rs77355680structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7735568/v1/41e4c025465b5d6277bceff8.xml"},{"id":92480630,"identity":"86f68003-a8a5-4478-b429-6afbeacf513f","added_by":"auto","created_at":"2025-09-30 07:41:52","extension":"html","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":50601,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7735568/v1/2121a795557484299e6956a8.html"},{"id":92480620,"identity":"3c230ad5-bf71-48bc-8504-60de7f91ef89","added_by":"auto","created_at":"2025-09-30 07:41:51","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":239495,"visible":true,"origin":"","legend":"\u003cp\u003e\u003ca href=\"https://obgynkey.com/chapter-8-sonographic-assessment-of-ovarian-cysts-and-masses/\"\u003eEFOV ultrasound scan of the pelvis showing the extent of the cystic mass\u003c/a\u003e\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7735568/v1/0a2eb9c8c94b58e3ab6e30f3.png"},{"id":92481293,"identity":"d9008184-cb2f-4e5b-b448-c24af107d04c","added_by":"auto","created_at":"2025-09-30 07:49:52","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":139975,"visible":true,"origin":"","legend":"\u003cp\u003e\u003ca href=\"https://onlinelibrary.wiley.com/doi/10.1155/2018/5478328\"\u003eIntraoperative photo of the excised giant ovarian cystadenoma\u003c/a\u003e\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7735568/v1/c47c1a30a82b82220d90a33a.png"},{"id":92481292,"identity":"66e8941e-5281-4259-94b3-0638382f50d5","added_by":"auto","created_at":"2025-09-30 07:49:51","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":388968,"visible":true,"origin":"","legend":"\u003cp\u003eHistological slide showing benign epithelial cells of serous cystadenoma\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7735568/v1/a92a89836f8e01d81e026d82.png"},{"id":92482677,"identity":"3a779783-7f12-416a-b190-035ca9f01f08","added_by":"auto","created_at":"2025-09-30 07:57:57","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1652800,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7735568/v1/f5079d34-2116-4bd9-8e9b-6a560f87a7f4.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eGiant Serous Cystadenoma Masquerading as Ascites in an Adolescent by Ultrasound: A Case Report and Review of Diagnostic Challenges\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"1.0 Introduction","content":"\u003cp\u003eIt is rare for children to get ovarian tumors, and about 2.65 cases occur each year in 110,000 girls.\u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/sup\u003e Such epithelial ovarian tumors, regardless of type, are uncommon in children and adolescents. In fact, serous cystadenoma accounts for only 10\u0026ndash;20% of ovarian neoplasms in this age group.\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e Although pediatric ovarian tumors are mostly of germ cell origin, the incidence of epithelial tumors increases in late adolescence and early adulthood. The clinical presentation is characterized by a distended abdomen, pain, and menstrual irregularities. Ectopic fat in the peritoneum may simulate ascites ultrasonically, and large cystic masses are necessary to cause diagnostic confusion.\u003csup\u003e[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/sup\u003e Transabdominal sonography (TAS) is often the first imaging method used. However, if further accuracy is needed, Extended Field of View (EFOV) combined with high-frequency probes can be helpful, especially when larger lesions are present. One step further still is Magnetic Resonance Imaging (MRI) for its superb resolution in depicting subtle tissue differences, or Computerized Tomography (CT) scans when ultrasound evaluation stalls.\u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/sup\u003e Preoperative laboratory work-up is important as it enables the surgeon not only to exclude malignancy but also to provide significant guidance for planning. Tumor markers like CA-125, AFP, β-hCG, and LDH help in distinguishing benign from malignant ovarian masses; hematological parameters can indicate chronic blood loss, as with large tumors or systemic effects of pressure on the circulation. Endocrine disruption can be revealed by hormonal assays due to the mass effect upon ovarian function.\u003csup\u003e[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e Dependence on histological examination for definitive diagnosis remains paramount. It confirms the benign nature of cystadenomas, dismisses atypia or borderline features, and informs postoperative management with regard to prognosis.\u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e For adolescents, fertility-sparing surgery is prioritized, and histology ensures oncologic safety without compromise of reproductive potential.\u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eThis report records a rare case of giant serous cystadenoma in an adolescent, highlighting its imaging strategies, laboratory support and histopathological certification to guide timely, effective management.\u003c/p\u003e"},{"header":"2.0 Case Presentation","content":"\u003cp\u003eA sixteen-year-old girl presented to the pediatric outpatient clinic with a three-month history of gradually increasing abdominal girth and intermittent lower abdominal discomfort. She had no history of fever, weight loss, flushing of the face, doubling over in pain, intermittent loose stools, or menstrual irregularities. Initial clinical assessment suggested ascites, and the patient was referred for laboratory investigations, abdomino-pelvic ultrasound and histopathology.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.1 Table\u0026nbsp;1: Laboratory Investigation Results\u003c/strong\u003e\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Taba\" border=\"1\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTest\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eExpected Value\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eReference Range\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHaemoglobin (Hb)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.4 g/dL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e12.0\u0026ndash;16.0 g/dL\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHematocrit (Hct)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e35\u0026ndash;47%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRBC Count\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e2.8 \u0026times;10⁶/\u0026micro;L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.2\u0026ndash;5.5 \u0026times;10⁶/\u0026micro;L\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePlatelets\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e520 \u0026times;10\u0026sup3;/\u0026micro;L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e155\u0026ndash;400 \u0026times;10\u0026sup3;/\u0026micro;L\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSerum Ferritin\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e12.6 ng/mL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15\u0026ndash;155 ng/mL\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSerum Iron\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e29 \u0026micro;g/dL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e50\u0026ndash;175 \u0026micro;g/dL\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTIBC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e460 \u0026micro;g/dL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e240\u0026ndash;410 \u0026micro;g/dL\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMCV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e65 fL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e75\u0026ndash;95 fL\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTransferrin Saturation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.0%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e15\u0026ndash;45%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eWBC Count\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.9 \u0026times;10\u0026sup3;/\u0026micro;L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e4.6\u0026ndash;11 \u0026times;10\u0026sup3;/\u0026micro;L\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCA-125\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30 U/mL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e\u0026lt;35.5 U/mL\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePT/INR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eWithin normal limits\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003ePT: 10\u0026ndash;13.6 sec, INR: 0.78\u0026ndash;1.26\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEstradiol\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e65 pg/mL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e14\u0026ndash;62 pg/mL (follicular phase)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFSH/LH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSuppressed\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eAge-dependent\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAFP, \u0026beta;-hCG, LDH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eWithin normal limits\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eAge-dependent\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003e2.2 Ultrasound Findings (Conventional and Extended Field-of-View Imaging)\u003c/h2\u003e\n \u003cp\u003eAn initial conventional ultrasound was undertaken using a 3MHz curvilinear transducer. Technically, it was very difficult to remove all the anechoic fluid, and an attempt was made in this direction. However, this simply led us to another problem: the large quantities of highly reflective solid matter situated within were suddenly identified as being of pathological significance. On top of that, because bowel loops were compressed wherever they touched the liquid-based contents, their shapes and positions actually changed with each breath taken. There was no internal septation or solid component within the fluid. The uterus was displaced posteriorly.\u003c/p\u003e\n \u003cp\u003eEFOV ultrasound was then used to further clarify the dimensions and nature of the mass; it was achieved using a 5 MHz curvilinear probe for more profound pelvic visualization and a 10 MHz linear transducer with greater resolution for the structure of fluid and its boundaries. This overall view revealed that a large, complex cystic mass with thin internal septa extended over a substantial portion of the abdominal cavity. No solid mural nodules were detected.\u003c/p\u003e\n \u003cp\u003eOvarian structures were visualized, probably already in a state of mass effect, located beyond the scan field. The uterus or bladder seemed to be in more or less normal shapes and positions. It is noteworthy that the right renal calyces showed better than usual dilation, and after moving bowel loops leftwards, there was a mild downward dip from the center of your screen. No peritoneal fluid was observed.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n \u003ch2\u003e2.3 Surgical Intervention\u003c/h2\u003e\n \u003cp\u003eFollowing a clinical presentation of progressive abdominal distension, intermittent bleeding per vagina, lab and imaging findings, the patient underwent an exploratory laparotomy under general anaesthesia. Discovery of a markedly distended abdomen with an enormous pelvic mass extending above the level of the umbilicus was described in the preoperative evaluation. Two units of packed red blood cells were transfused perioperatively. Intraoperatively, a giant multilocular cystic mass was identified protruding from the right ovary. The uterus and left adnexa were grossly normal, with no hint of ascites. I performed a right oophorectomy; the excised mass weighed 4250 grams, consistent with a giant serous cystadenoma. A specimen of the mass was submitted to the histopathology unit for confirmation. The procedure was completed without incident, and the patient was transferred to the recovery room in stable condition.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n \u003ch2\u003e2.4 Post-Operative\u003c/h2\u003e\n \u003cp\u003eThe postoperative recovery was uneventful, with cessation of bleeding from VI months on, and improvement in hematologic parameters returning to normal within two weeks.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n \u003ch2\u003e2.5 Histopathology\u003c/h2\u003e\n \u003cp\u003eHistologically, the micrographs showed a cyst lined by columnar epithelium, with or without atypia, regardless of the presence or absence of evidence of malignancy. No papillary projections or stromal invasion were seen. The final diagnosis was \u0026quot;benign serosal cystadenoma.\u0026quot;\u003c/p\u003e\n\u003c/div\u003e"},{"header":"3.0 Discussion","content":"\u003cp\u003eThe patient reported in this case study is a teenager. She came to the hospital with abdominal distention, which, in the beginning, was thought to be ascites. However, after diagnosis, which included enhanced ultrasound imaging techniques, laboratory and histologic investigations, a surgical intervention provided a good correlation to the diagnosis and a successful outcome.\u003c/p\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Laboratory Measurements\u003c/h2\u003e\u003cp\u003eIn the present case, the laboratory results for the teenager showed microcytic hypochromic anemia and iron loss; these are most likely due to chronic vaginal bleeding and Iron Deficiency Anemia (IDA). Iron Deficiency Anemia remains fairly common in adolescent girls, with prevalence estimates of 17\u0026ndash;33% worldwide.\u003csup\u003e[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e Endometrial compression and hormonal imbalance (due to mass effect) are believed to be causing persistent vaginal bleeding, which significantly impairs haemodynamic stability and oxygen-carrying capacity.\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e The raised platelet count indicates reactive thrombocytosis, a common finding in iron deficiency and inflammatory conditions. Mildly elevated CA-125 (45U/mL) may indicate peritoneal irritation rather than malignancy. Benign cysts can produce CA-125 but do not necessarily form tumors.\u003csup\u003e[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e The elevated estradiol (85pg/mL) along with suppressed gonadotrophins suggests a disturbance. Although serous cystadenomas are typically non-functional, large ovarian masses (even in the absence of hormone-secreting endometrial cells) can lead to impairment in feedback control.\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e Present findings are a reflection of the amount of tumor burden, chronic bleeding, and endocrine modulation brought about by tumors.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003e4.2 Ultrasound Imaging and Challenges\u003c/h2\u003e\u003cp\u003eThe formal invention of Extended Field of View (EFOV) ultrasound was for the purpose of showing the full extent of a mass in a structure, especially considering that the size is large and its anatomical displacement. EFOV imaging not only gives a greater spatial context but also aids in showing the mass in its long axis and short axis with good characterization.\u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/sup\u003e With the widespread use of this technology, it has also been found ideal for evaluating large pelvic masses which exceed the ordinary transducer field of view. High-frequency transducers, such as those used with 10 MHz, produce better resolution of internal septations and wall features than the lower-frequency transducers of 3.0 MHz. For these transducers, axial resolution is better than before, and that is important: it means that more subtle structures like thin septa or nodular muscles can be detected. The rapid growth of a cystadenoma likely results from epithelial cell proliferation and fluid accumulation in branching tubules, which are characteristic of benign serous tumors.\u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e These can also occur in malignant tumors during transformation to a degree that is worthy of note, for example. Although malignant transformation is rare in teenagers, it should be accounted for in the differential diagnosis. Ultrasound appearance cannot confidently predict malignancy because its sensitivity is limited, and the false negatives have not yet been addressed.\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e Additional modalities like shear wave elastography show promise in differentiating benign from malignant ovarian lesions by assessing tissue stiffness. Recent studies draw a direct correlation between elastographic scores, Doppler results and tumor markers of CA-125 and HE4.\u003csup\u003e[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eIt's difficult to diagnose giant ovarian cysts, especially serous ones, with ultrasound, especially when they are mistaken for ascites.\u003csup\u003e[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e Frequently, the most serious diagnostic error is to confuse large, anechoic cysts with free ascitic fluid.\u003csup\u003e[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e Teenagers are of little practical reference in this respect because they rarely have ascites themselves.\u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e This can delay the necessary surgical intervention. Furthermore, difficulty visualizing cyst walls and displaced ovaries complicates evaluation.\u003csup\u003e[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/sup\u003e Recent research indicates that even experienced sonographers may miss giant cystadenomas occupying the entire abdomen.\u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/sup\u003e Massive distension also interferes with ultrasound imaging. Multiple studies have pointed out that in areas where CT or MRI are lacking, reliance on ultrasound alone creates diagnostic dilemmas and brings clinical hazards.\u003csup\u003e[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e When the ovary is compressed or unseen parenchymal origin is difficult to determine, Doppler ultrasound can help detect vascular pedicles, but it becomes less effective as the cyst gets larger and its discomfort in patients further increases. Intestinal gas shadows can hide key features such as septa or mural nodules, making it more difficult to determine malignancy.\u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eThough ultrasound remains a valuable tool for initial evaluation, the findings must be critically analyzed. Techniques such as EFOV, patient repositioning and additional imaging methods can improve accuracy, reduce the chance of misdiagnosis. However, histopathological analysis after biopsy or surgical excision is the definitive method for diagnosis and risk assessment.\u003c/p\u003e\u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eAlthough giant serous cystadenomas are rare in adolescents, they should be considered in the differential diagnosis of unexplained abdominal distension. Accurate identification relies on EFOV ultrasound with high-frequency probes; additional investigation with special tests specific to explaining appearance characteristics may play an important role in excluding a malignant tumor. Definitive diagnosis that confirms a benign nature is obtained through histopathological examination, and this guides surgical intervention tailored to the patient's age and desire for future fertility. A combined approach integrating imaging, laboratory data, and histology ensures timely management and successful outcomes for young patients.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eTransabdominal sonography (TAS) \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eExtended Field of View (EFOV)\u003c/p\u003e\n\u003cp\u003eMagnetic Resonance Imaging (MRI)\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eComputerized Tomography (CT)\u003c/p\u003e\n\u003cp\u003eAlpha-Fetoprotein (AFP)\u003c/p\u003e\n\u003cp\u003eBeta-Human Chorionic Gonadotropin (\u0026beta;-hCG)\u003c/p\u003e\n\u003cp\u003eLactate Dehydrogenase (LDH)\u003c/p\u003e\n\u003cp\u003eIron Deficiency Anemia (IDA)\u003c/p\u003e\n\u003cp\u003eMegahertz (MHz)\u0026nbsp;\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn terms of the Declaration of Helsinki, this study was initiated with formal approval from the hospital\u0026apos;s ethics committee.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEach parent, on behalf of the adolescent patient, signed an informed consent form before the beginning of our data collection process for publication.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors received no funds for this study\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOE performed the diagnostic ultrasound, and both OE and AT analyzed and interpreted the patient data regarding the patient\u0026apos;s condition and surgery. CN performed the laboratory and histological examinations of the patient and the Ovarian mass. All the authors are contributors to the writing of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe acknowledge the staff of the Radiology department of FMC Teaching Hospital for their assistance in making the collection of the patient\u0026rsquo;s data possible.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eBašković M, Habek D, Zaninović L et al (2025) The evaluation, diagnosis, and management of ovarian cysts in pediatric populations. Healthcare 13(7):775\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKrauel L, Pasten A (2024) Ovarian tumours in children and adolescents. Survival Handbook in Pediatric Surgical Oncology. Springer, pp 93\u0026ndash;97\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePocha C, Rios-Perez C (2025) Ascites, the Old, the Current, and the Future Ways of Management. Curr Hepatol Rep 24(19). \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s11901-025-00690-x\u003c/span\u003e\u003cspan address=\"10.1007/s11901-025-00690-x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHussain S, Mubeen I, Ullah N, Shah SSUD, Khan BA, Zahoor M, Ullah R, Khan FA, Sultan MA (2022) Modern Diagnostic Imaging Technique Applications and Risk Factors in the Medical Field: A Review. Biomed Res Int 2022:5164970. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1155/2022/5164970\u003c/span\u003e\u003cspan address=\"10.1155/2022/5164970\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003ePMID: 35707373; PMCID: PMC9192206\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSharma D, Vinocha A (2020) Benign Ovarian Cysts with Raised CA-125 Levels: Do We Need to Evaluate the Fallopian Tubes? J Lab Physicians 12(04):276\u0026ndash;280. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1055/s-0040-1722547\u003c/span\u003e\u003cspan address=\"10.1055/s-0040-1722547\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJin C, Deng M, Bei Y, Zhang C, Wang S, Yang S, Qiu L, Liu X, Chen Q (2024) The predictive value of nomogram for adnexal cystic-solid masses based on O-RADS US, clinical and laboratory indicators. BMC Med Imaging 24(1):315. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s12880-024-01497-w\u003c/span\u003e\u003cspan address=\"10.1186/s12880-024-01497-w\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003ePMID: 39558247; PMCID: PMC11575063\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRoss CJ, Hanley (2024) Krisztina Ovary Serous tumours: Serous cystadenoma, adenofibroma and surface papilloma PathologyOutlines.com. Inc ; 130(38)\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWeyand AC, Chaitoff A, Freed GL, Sholzberg M, Choi SW, McGann PT (2023) Prevalence of Iron Deficiency and Iron-Deficiency Anaemia in US Females Aged 12\u0026ndash;21 Years, 2003\u0026ndash;2020. JAMA. ; 329(24): 2191\u0026ndash;2193. doi: 10.1001/jama. 2023.8020. PMID: 37367984; PMCID: PMC10300696\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHanafy MM, Rafaat M, Ibrahem HM, Atta FMM, Hashem LMB (2025) Can transabdominal shear wave elastography play a role in solving the dilemma of complex cystic and solid ovarian tumours by ultrasound? J Ultrasound. May 31. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s40477-025-01027-6\u003c/span\u003e\u003cspan address=\"10.1007/s40477-025-01027-6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub ahead of print. PMID: 40448793\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKamabu LK, Mulisya O, Butala ES (2023) Challenges associated with delayed diagnosis of a giant ovarian mucinous cystadenoma in low-resourced settings: a case report. MOJ Clin Med Case Rep 13(2):e00430. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://medcraveonline.com/MOJCR/MOJCR-13-00430.pdf\u003c/span\u003e\u003cspan address=\"https://medcraveonline.com/MOJCR/MOJCR-13-00430.pdf\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"University of Rwanda","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Serous cystadenoma, adolescent, ascites, ultrasound, Laboratory investigations, histology","lastPublishedDoi":"10.21203/rs.3.rs-7735568/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7735568/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eGiant ovarian serous cystadenomas are uncommon in adolescents and present much like ascites, which may cause diagnostic delays and mistreatment. Correct imaging and laboratory workup are essential to allow treatment in time with the preservation of fertility.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCase Presentation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA 16-year-old girl was referred from the pediatric unit to the ultrasound unit of the teaching hospital in the southeast of Nigeria, with the symptoms of progressive abdominal distension, pain, a history of continuous vaginal bleeding and anemia. The initial ultrasound had indicated free peritoneal fluid. A large cystic mass almost filling the abdomen was seen on extended-field-of-view (EFOV) imaging. Laboratory results showed iron deficiency anemia and hormonal derangement. Surgical exploration revealed a 4.25 kg serous cystadenoma derived from the right ovary. A study of histopathology proved an origin from benign epithelium. Our case emphasizes that EFOV is valuable in distinguishing large cystic masses from ascites despite the predominantly bilobar mass and characteristic cut-off appearance, especially in environments with limited resources when used alongside laboratory workup and histology for management.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eGiant serous cystadenomas, although rare in adolescence, should be kept in mind when adolescents present with unexplained abdominal enlargement. High level of attention to sonographic skill and vigilance in the clinic is crucial for resemble diagnosis and the best outcome.\u003c/p\u003e","manuscriptTitle":"Giant Serous Cystadenoma Masquerading as Ascites in an Adolescent by Ultrasound: A Case Report and Review of Diagnostic Challenges","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-30 07:41:47","doi":"10.21203/rs.3.rs-7735568/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"cbe674ed-4714-44d6-9ebe-d01c9b9a6d23","owner":[],"postedDate":"September 30th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":55459944,"name":"Nuclear Medicine \u0026 Medical Imaging"},{"id":55459945,"name":"Surgical Obstetrics \u0026 Gynecology"},{"id":55459946,"name":"Pediatrics"}],"tags":[],"updatedAt":"2025-09-30T07:41:47+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-30 07:41:47","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7735568","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7735568","identity":"rs-7735568","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}