Thymic hyperplasia presenting with respiratory distress in a male newborn: A case report

Thymic hyperplasia presenting with respiratory distress in a male newborn: A case report | 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 Thymic hyperplasia presenting with respiratory distress in a male newborn: A case report Alazar Wogayehu Gebrehana, Teshome Gletaw, Yalew Melkamu, Mulugeta Negusu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5515414/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: Although thymic enlargement is a common and physiological finding of neonates and infants, symptomatic hyperplasia is a very rare condition. Case presentation: We report a 21-hour male neonate who presented with fast and noisy breathing and failure to suck for 12 hours duration. He had signs of respiratory distress and was initially started on treatment for early-onset sepsis without any improvement. Later imaging showed a thymic enlargement which was then successfully treated with steroids. Conclusion: Symptomatic thymic hyperplasia is an uncommon condition in the neonatal period. Steroids can be effective in the treatment of thymic hyperplasia help shrink the enlarged thymus and avoid unnecessary surgery. Thymic hyperplasia thymic enlargement thymus steroids true thymic hyperplasia Figures Figure 1 Figure 2 Figure 3 Background The thymus is an important organ in children and functions as a site of T cell proliferation, regulation, and maturity. It is derived embryologically from the 3 rd pharyngeal pouch(1). Thymic hyperplasia(TH) is an increase in the size and weight of the thymus. Thymic enlargement is commonly seen casually on chest radiographs of newborns and infants and is asymptomatic. Here, we report a male newborn who presented with a symptomatic TH resulting in respiratory distress. We will review the different types of TH and explore the different treatment options and their outcomes. Case Presentation A 21-hour-old male newborn was presented to the neonatal intensive care unit of Gondar University Hospital for a complaint of fast and noisy breathing which started at 12 hours of age. The newborn was born to a 28-year-old para 2 mother. The mother had Antenatal care follow-up during the pregnancy and took all her vitamin supplements and vaccinations. She was also screened for syphilis and HIV infection and found to be negative. Labor and delivery were also uneventful with a total duration of labor of 13 hours and rupture of membranes 4 hours before delivery. Delivery was via spontaneous vaginal delivery to effect a 3900-gram male alive neonate with 1 st and 5 th -minute Apgar scores of 8 and 9 respectively. The mother and newborn were discharged after 6 hours of observation. Physical examination was notable for an acutely sick newborn with signs of respiratory distress and tachypnea of 68 breaths/minute. The neonate maintains a saturation of 97% on room air. Chest auscultations revealed inspiratory stridor and bilateral coarse crepitations. All other physical findings were normal. With the provisional diagnosis of Early onset sepsis with congenital pneumonia the newborn was promptly put on intra-nasal oxygen and started on intravenous Ampicillin and gentamycin. Complete blood count showed leucocytosis of 20000 with an absolute neutrophil count of 10800. Blood culture showed no growth and C- C-reactive protein was normal. After 48 hours of antibiotics initiation patient showed little improvement and a Posterio-anterior and lateral Chest radiograph was obtained and it revealed a Wide anterior mediastinal mass with left side pushed cardiac shadow(Figure 1). Chest Ultrasound revealed anterior mediastinal homogenous texture soft tissue mass 7x5 cm in size at the site of thymus. A chest CT was also obtained on the same day and it showed an anterior mediastinal homogenous non-enhancing mass measuring 4cm in anteroposterior dimension with no calcification with possible differential diagnosis of thymic hyperplasia and thymic teratoma(Figure 2). Serum Alpha-fetoprotein was normal. Ultrasound-guided fine needle aspiration was done and it confirmed the diagnosis of thymic hyperplasia. On the third day of admission, it was decided to start a trial of steroids with intravenous dexamethasone of 0.6mg/kg every six hours. The stridor and signs of respiratory distress significantly improved over the next 3 days and a repeat chest ultrasound showed decreasing thymic shadow thickness. Dexamethasone was subsequently continued for an additional 4 days and then tapered off and discontinued after 2 weeks. The newborn was fully asymptomatic by this time off oxygen support and feeding well. No corticosteroid side effects as hypertension, glucosuria, and electrolyte disturbances have been observed. On the 16 th day of admission, the Chest radiograph showed complete resolution of the thymic mass(Figure 3) and the patient was later discharged. Followup evaluation at the first and third month of age revealed no abnormalities or signs of recurrence. Discussion and conclusions The thymus is a bi-lobed gland that is located in the central compartment of the thoracic cavity, on top of the heart and behind the sternum. It is the primary site of T-lymphocyte development and it is embryologically derived from the third pharyngeal pouch. The size of the thymus varies with age and it gradually decreases during the first 3 to 4 years of life( 2). Based on morphologic and clinical criteria, TH can be classified into 3 types: (A) True thymic hyperplasia(TTH) (a thymic enlargement beyond the upper limits of normal for the age but accompanied by a microscopically and structurally normal gland.) (B) Lymphofollicular hyperplasia, (which consists of predominant hyperplastic lymphoid follicles regardless of size and weight of gland) and (C) Massive thymic hyperplasia(MTH), (a variant of TTH where the mass should be greater than the cardiac shadow on PA chest radiograph, thymus weight should be several times more than the expected weight for age and should represent more than 2% of the body mass with microscopically normal gland.) (3). Although thymic enlargement is relatively common in infants, a symptomatic large TTH is a very rare finding, especially in those less than 1 year of age with one literature review stating that they only found 10 cases of THH below the age of 1 year between 1975 and 2020(TJP 2021). Another literature review found 14 cases of MTH in those under 2 years of age between 1976 and 2018 with a median age of presentation of 10.3 months(4). Clinical presentations of thymic hyperplasia might be the results of mediastinal compression effects like respiratory distress, dysphagia, or airway obstruction. TH might also present with acute or recurrent pulmonary infections or less commonly as an incidental finding during imaging (4). Differential diagnoses for a mediastinal mass in a neonate include Germ cell tumors of which the most common is teratoma, lymphatic disorders including lymphangiomas and lymphomas, and less commonly benign and malignant thymic tumors( 5,6). Primary thymic lesions (such as thymic cysts, thymolipomas, and thymic hyperplasia) represent only 2.5% of mediastinal tumors in children while thymomas represent about 1% and are usually aggressive(7). Diagnosis of TH can be suggested by imaging. Homogeneous density on imaging, suggests thymic hyperplasia than other differential considerations in newborns. Although multimodal imaging has an excellent diagnostic value for TTH, MRI is the recommended imaging of choice as it can more easily identify mediastinal masses, which are directly contiguous with and follow the same signal features as the main body of the thymus(8). For those cases in which imaging reveals heterogeneity other differentials like germ cell tumors can be considered and tumor markers( serum β-HCG and α-fetoprotein tests (AFP) and FNAC have to be done to confirm the diagnosis. Pathology in TTH will show histologically normal thymic tissue consisting of lobules with well‐defined cortical and medullary cells. Literature on the treatment of choice for TTH is somehow controversial and there are no clear guidelines for therapy. One option for treatment is a trial of corticosteroids. Corticosteroids are potent to reduce the volume of the thymus and achieve its partial involution and thereby may prevent invasive surgery in symptomatic patients(9). Clinical studies indicate that thymectomy in children younger than 1 year results in decreased counts of peripheral blood T cell subsets. Therefore, thymectomy should be avoided whenever possible(10). However, there is not much known about the dose, duration and type of steroid to be used. Furthermore, some literature found steroids to be ineffective in decreasing the mass needing surgical excision. (3,11,12). One case report and literature review stated that six out of fourteen(42.9%) patients with MTH were initially given steroid treatment, with no benefits: in one case, the thymus regrew after therapy was suspended; in the other five cases, it was ineffective also due to insignificant shrinkage(4). In contrast, similar to our case, a case report has reported a successful treatment of a symptomatic TTH in a five-week-old infant with steroids(13). They used a once daily 4mg/kg methylprednisolone for one week, reduced stepwise, and stopped after four weeks. The second option of treatment widely advocated by most authors is surgical excision of the thymus. Most use sternothoracotomy but there are reports of successful excision using thoracotomy and VATS(video-assisted thoracoscopic surgery)(2,11). There are also reports of conservative management for those asymptomatic or incidentally found TTH(14). Spontaneous regression of THH also uncommon has also been reported(15,16,17). Outcomes after surgical treatment are excellent and recurrence is very rare. In conclusion, our case report shows a very rare presentation of symptomatic TTH in a 21-day neonate which was treated successfully with intravenous dexamethasone and highlights a trial of corticosteroids could prove effective in regressing the mass and resolving symptoms with the added benefit of avoiding invasive surgical intervention. Abbreviations TH Thymic hyperplasia CT Computerized tomography TTH True thymic hyperplasia MTH Massive thymic hyperplasia FNAC Fine needle aspiration cytology Declarations Acknowledgments The authors gratefully acknowledge that all team members dedicate their best efforts to care for our patients. Authors contributions AWG & TG - Writing- review & editing, Writing- original draft, Conceptualization. YM & MN- Writing- review & editing. Funding This research received no funding or grant support. Availability of data and materials All data generated and analyzed during the study are included in this published article. Clinical Trial Number: Not applicable Ethics approval and consent to participate This study was conducted by the fundamental principles of the Declaration of Helsinki. Consent for publication Written informed consent was obtained from the patient's mother for the publication of this case report and any accompanying images. A copy of the written consent is available for review by the corresponding author. Competing interests The authors declare that they have no competing interests. References Lee YM, Koh MT, Omar A, Majid A. Hyperplasia of thymic gland. Singap Med J. 1996;37:288–90. Tan Z, Ying LY, Zhang ZW, Li JH, Gao Z, Qi JC. True thymic hyperplasia in an infant. J Pediatr Surg. 2010;45:1711–3. 10.1016/j.jpedsurg.2010.05.001 . Eifinger F, Ernestus K, Benz-Bohm G, et al. True thymic hyperplasia associated with severe thymic cyst bleeding in a newborn: case report and review of the literature. Ann Diagn Pathol. 2007;11(5):358–62. 10.1016/j.anndiagpath.2006.04.007 . Tadiotto E, Clemente M, Pecoraro L, Piacentini G, Degani D, Pietrobelli A. Massive thymic hyperplasia in a 15-month-old boy: Case report and literature review. Clin Case Rep. 2018;7(1):27–31. 10.1002/ccr3.1896 . Published 2018 Nov 10. Nariman M, Willi W, Hansjörg S, Martin B, Michael G, Konrad R. Case report: True thymic hyperplasia in a 30-Day-Old boy. Klin Padiatr. 2021;233(6):299–302. 10.1055/a-1557-1427 . Chand MT, Edens J, Lin TT, Goshorn D, Pham T. Congenital thymoma. Autops Case Rep. 2021;11:e2021327. 10.4322/acr.2021.327 . Published 2021 Sep 22. Grosfeld JL, Skinner MA, Rescorla FJ, West KW, Scherer LR. Mediastinal tumors in children: experience with 196 cases. Ann Surg Oncol. 1994;1(2):121–7. Ka KW, Elisa F, Morand P. F-18 FDG PET/CT study showing cervical extension of thymic tissue. Clin Nucl Med. 2008;33(8):547–8. 10.1097/ RLU.0b013e31817dec53. Sauter ER, Arensman RM, Falterman KW. Thymic enlargement in children. Am Surg. 1991;57(1):21–3. Khariwala SS, Nicollas R, Triglia JM, et al. Cervical presentations of thymic anomalies in children. Int J Pediatr Otorhinolaryngol. 2004;68(7):909–14. Jiao J, Yu J, Chen C, Chen T, Zheng T, He L, Zeng Q. Thoracoscopic approach for massive thymic hyperplasia in an infant: Case report and literature review. Front Pediatr. 2023;11:1144384. 10.3389/fped.2023.1144384 . Yang M, Zeng L, Ji Y, Xiang B, Xu ZC. Massive true thymic hyperplasia in a 3-month-old infant: case report and literature review. Turk J Pediatr. 2021;63(4):721–6. 10.24953/turkjped.2021.04.022 . Wolff M, Demirakca S, Kilian A, Schroten, Horst, Tenenbaum, Tobias. (2011). Laryngo-Tracheal Displacement and Respiratory Distress in an Infant with Congenital Thymic Hyperplasia. ISRN Pulmonology. 2011. 10.5402/2011/659103 Nguyen R, Coleman JL, Howard SC, Metzger ML. Watchful waiting for some children with a mediastinal mass: the potential role for 1⁸F-fluorodeoxyglucose positron emission tomography: a case report and review of the literature. BMC Pediatr. 2013;13:103. Dimitriou G, Greenough A, Rafferty G, Rennie J, Karani J. Respiratory distress in a neonate with an enlarged thymus. Eur J Pediatr. 2000;159(4):237–8. 10.1007/s004310050061 . Adane L, Arega G, Tenaw S. A massive thymus enlargement in a neonate with sepsis: A case report. J Clin Images Med Case Rep. 2024;5(4):2977. Piednoir P, Taylor G, Gayat E, Devys JM. Benign thymic hyperplasia: an unexpected cause of respiratory distress during inhalatory induction of anesthesia. Paediatr Anaesth. 2008;18(12):1220–1. 10.1111/j.1460-9592.2008.02707.x . Additional Declarations No competing interests reported. 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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-5515414","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":403574589,"identity":"e0f9c7e8-6922-42fc-8f2b-37d51a07ad4b","order_by":0,"name":"Alazar Wogayehu 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1","display":"","copyAsset":false,"role":"figure","size":351398,"visible":true,"origin":"","legend":"\u003cp\u003eWide anterior mediastinal mass with left side pushed cardiac shadow.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-5515414/v1/e0fa36fcd9d0e4c4002ae685.png"},{"id":74295331,"identity":"44bc41a6-59f9-4850-b66a-7eee2a413120","added_by":"auto","created_at":"2025-01-20 17:55:00","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":241762,"visible":true,"origin":"","legend":"\u003cp\u003eAnterior mediastinal homogeneous non-enhancing mass in anteroposterior dimension with no calcification.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-5515414/v1/113cc6dabb5867eb8c48e1be.png"},{"id":74294355,"identity":"0ce3bc6d-9e50-4a6d-a92c-c7848d408a64","added_by":"auto","created_at":"2025-01-20 17:47:00","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":265274,"visible":true,"origin":"","legend":"\u003cp\u003eNormal chest radiograph with complete resolution of mediastinal mass.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-5515414/v1/cf8627375dff441517448ae1.png"},{"id":74295332,"identity":"1ef388f5-8c74-429b-9b76-b921897da6c0","added_by":"auto","created_at":"2025-01-20 17:55:05","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1602355,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5515414/v1/249759af-3717-429e-a078-f56398588b75.pdf"},{"id":74294353,"identity":"e9f009ae-03fe-499a-92f4-c7c6e3c8d268","added_by":"auto","created_at":"2025-01-20 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It is derived embryologically from the 3\u003csup\u003erd\u003c/sup\u003e pharyngeal pouch(1). Thymic hyperplasia(TH) is an increase in the size and weight of the thymus. Thymic enlargement is commonly seen casually on chest radiographs of newborns and infants and is asymptomatic. Here, we report a male newborn who presented with a symptomatic TH resulting in respiratory distress. We will review the different types of TH and explore the different treatment options and their outcomes.\u003c/p\u003e"},{"header":"Case Presentation","content":"\u003cp\u003eA 21-hour-old male newborn was presented to the neonatal intensive care unit of Gondar University Hospital for a complaint of fast and noisy breathing which started at 12 hours of age. The newborn was born to a 28-year-old para 2 mother. The mother had Antenatal care follow-up during the pregnancy and took all her vitamin supplements and vaccinations. She was also screened for syphilis and HIV infection and found to be negative. Labor and delivery were also uneventful with a total duration of labor of 13 hours and rupture of membranes 4 hours before delivery. Delivery was via spontaneous vaginal delivery to effect a 3900-gram male alive neonate with 1\u003csup\u003est\u003c/sup\u003e and 5\u003csup\u003eth\u003c/sup\u003e-minute Apgar scores of 8 and 9 respectively. The mother and newborn were discharged after 6 hours of observation.\u003c/p\u003e\n\u003cp\u003ePhysical examination was notable for an acutely sick newborn with signs of respiratory distress and tachypnea of 68 breaths/minute. The neonate maintains a saturation of 97% on room air. Chest auscultations revealed inspiratory stridor and bilateral coarse crepitations. All other physical findings were normal. With the provisional diagnosis of Early onset sepsis with congenital pneumonia the newborn was promptly put on intra-nasal oxygen and started on intravenous Ampicillin and gentamycin.\u003c/p\u003e\n\u003cp\u003eComplete blood count showed leucocytosis of 20000 with an absolute neutrophil count of 10800. Blood culture showed no growth and C- C-reactive protein was normal. After 48 hours of antibiotics initiation patient showed little improvement and a Posterio-anterior and lateral Chest radiograph was obtained and it revealed a Wide anterior mediastinal mass with left side pushed cardiac shadow(Figure 1). Chest Ultrasound revealed anterior mediastinal homogenous texture soft tissue mass 7x5 cm in size at the site of thymus. A chest CT was also obtained on the same day and it showed an anterior mediastinal homogenous non-enhancing mass measuring 4cm in anteroposterior dimension with no calcification with possible differential diagnosis of thymic hyperplasia and thymic teratoma(Figure 2). Serum Alpha-fetoprotein was normal. Ultrasound-guided fine needle aspiration was done and it confirmed the diagnosis of thymic hyperplasia.\u003c/p\u003e\n\u003cp\u003eOn the third day of admission, it was decided to start a trial of steroids with intravenous dexamethasone of 0.6mg/kg every six hours. The stridor and signs of respiratory distress significantly improved over the next 3 days and a repeat chest ultrasound showed decreasing thymic shadow thickness.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDexamethasone was subsequently continued for an additional 4 days and then tapered off and discontinued after 2 weeks. The newborn was fully asymptomatic by this time off oxygen support and feeding well. No corticosteroid side effects as hypertension, glucosuria, and electrolyte disturbances have been observed. On the 16\u003csup\u003eth\u003c/sup\u003e day of admission, the Chest radiograph showed complete resolution of the thymic mass(Figure 3) and the patient was later discharged. Followup evaluation at the first and third month of age revealed no abnormalities or signs of recurrence.\u003c/p\u003e"},{"header":"Discussion and conclusions","content":"\u003cp\u003eThe thymus is a bi-lobed gland that is located in the central compartment of the thoracic cavity, on top of the heart and behind the sternum. It is the primary site of T-lymphocyte development and it is embryologically derived from the third pharyngeal pouch. The size of the thymus varies with age and it gradually decreases during the first 3 to 4 years of life( 2).\u003c/p\u003e\n\u003cp\u003eBased on morphologic and clinical criteria, TH can be classified into 3 types: (A) True thymic hyperplasia(TTH) (a thymic enlargement beyond the upper limits of normal for the age but accompanied by a microscopically and structurally normal gland.) (B) Lymphofollicular hyperplasia, (which consists of predominant hyperplastic lymphoid follicles regardless of size and weight of gland) and (C) Massive thymic hyperplasia(MTH), (a variant of TTH where the mass should be greater than the cardiac shadow on PA chest radiograph, thymus weight should be several times more than the expected weight for age and should represent more than 2% of the body mass with microscopically normal gland.) (3).\u003c/p\u003e\n\u003cp\u003eAlthough thymic enlargement is relatively common in infants, a symptomatic large TTH is a very rare finding, especially in those less than 1 year of age with one literature review stating that they only found 10 cases of THH below the age of 1 year between 1975 and 2020(TJP 2021). Another literature review found 14 cases of MTH in those under 2 years of age between 1976 and 2018 with a median age of presentation of 10.3 months(4).\u003c/p\u003e\n\u003cp\u003eClinical presentations of thymic hyperplasia might be the results of mediastinal compression effects like respiratory distress, dysphagia, or airway obstruction. TH might also present with acute or recurrent pulmonary infections or less commonly as an incidental finding during imaging (4).\u003c/p\u003e\n\u003cp\u003eDifferential diagnoses for a mediastinal mass in a neonate include Germ cell tumors of which the most common is teratoma, lymphatic disorders including lymphangiomas and lymphomas, and less commonly benign and malignant thymic tumors( 5,6).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePrimary thymic lesions (such as thymic cysts, thymolipomas, and thymic hyperplasia) represent only 2.5% of mediastinal tumors in children while thymomas represent about 1% and are usually aggressive(7).\u003c/p\u003e\n\u003cp\u003eDiagnosis of TH can be suggested by imaging. Homogeneous density on imaging, suggests thymic hyperplasia than other differential considerations in newborns. Although multimodal imaging has an excellent diagnostic value for TTH, MRI is the recommended imaging of choice as it can more easily identify mediastinal masses, which are directly contiguous with and follow the same signal features as the main body of the thymus(8).\u003c/p\u003e\n\u003cp\u003eFor those cases in which imaging reveals heterogeneity other differentials like germ cell tumors can be considered and tumor markers( serum \u0026beta;-HCG and \u0026alpha;-fetoprotein tests (AFP) and FNAC have to be done to confirm the diagnosis. Pathology in TTH will show histologically normal thymic tissue consisting of lobules with well‐defined cortical and medullary cells.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eLiterature on the treatment of choice for TTH is somehow controversial and there are no clear guidelines for therapy. One option for treatment is a trial of corticosteroids. Corticosteroids are potent to reduce the volume of the thymus and achieve its partial involution and thereby may prevent invasive surgery in symptomatic patients(9). Clinical studies indicate that thymectomy in children younger than 1 year results in decreased counts of peripheral blood T cell subsets. Therefore, thymectomy should be avoided whenever possible(10).\u003c/p\u003e\n\u003cp\u003eHowever, there is not much known about the dose, duration and type of steroid to be used. Furthermore, some literature found steroids to be ineffective in decreasing the mass needing surgical excision. (3,11,12). One case report and literature review stated that six out of fourteen(42.9%) patients with MTH were initially given steroid treatment, with no benefits: in one case, the thymus regrew after therapy was suspended; in the other five cases, it was ineffective also due to insignificant shrinkage(4). In contrast, similar to our case, a case report has reported a successful treatment of a symptomatic TTH in a five-week-old infant with steroids(13). They used a once daily 4mg/kg methylprednisolone for one week, reduced stepwise, and stopped after four weeks.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe second option of treatment widely advocated by most authors is surgical excision of the thymus. Most use sternothoracotomy but there are reports of successful excision using thoracotomy and VATS(video-assisted thoracoscopic surgery)(2,11).\u003c/p\u003e\n\u003cp\u003eThere are also reports of conservative management for those asymptomatic or incidentally found TTH(14).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eSpontaneous regression of THH also uncommon has also been reported(15,16,17). Outcomes after surgical treatment are excellent and recurrence is very rare.\u003c/p\u003e\n\u003cp\u003eIn conclusion, our case report shows a very rare presentation of symptomatic TTH in a 21-day neonate which was treated successfully with intravenous dexamethasone and highlights a trial of corticosteroids could prove effective in regressing the mass and resolving symptoms with the added benefit of avoiding invasive surgical intervention.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eTH Thymic hyperplasia\u003c/p\u003e\n\u003cp\u003eCT \u0026nbsp;Computerized tomography\u003c/p\u003e\n\u003cp\u003eTTH \u0026nbsp;True thymic hyperplasia\u003c/p\u003e\n\u003cp\u003eMTH \u0026nbsp;Massive thymic hyperplasia\u003c/p\u003e\n\u003cp\u003eFNAC Fine needle aspiration cytology\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors gratefully acknowledge that all team members dedicate their best efforts to care for our patients.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAWG \u0026amp; TG -\u003c/strong\u003e \u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eWriting- review \u0026amp; editing, Writing- original draft, Conceptualization.\u0026nbsp;\u003cstrong\u003eYM \u0026amp; MN-\u0026nbsp;\u003c/strong\u003eWriting- review \u0026amp; editing.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research received no funding or grant support.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data generated and analyzed during the study are included in this published article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical Trial Number:\u0026nbsp;\u003c/strong\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was conducted by the fundamental principles of the Declaration of Helsinki.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWritten informed consent was obtained from the patient\u0026apos;s mother for the publication of this case report and any accompanying images. A copy of the written consent is available for review by the corresponding author.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eLee YM, Koh MT, Omar A, Majid A. Hyperplasia of thymic gland. Singap Med J. 1996;37:288\u0026ndash;90.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTan Z, Ying LY, Zhang ZW, Li JH, Gao Z, Qi JC. True thymic hyperplasia in an infant. 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Benign thymic hyperplasia: an unexpected cause of respiratory distress during inhalatory induction of anesthesia. Paediatr Anaesth. 2008;18(12):1220\u0026ndash;1. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/j.1460-9592.2008.02707.x\u003c/span\u003e\u003cspan address=\"10.1111/j.1460-9592.2008.02707.x\" targettype=\"DOI\" 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":"","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":"Thymic hyperplasia, thymic enlargement, thymus, steroids, true thymic hyperplasia","lastPublishedDoi":"10.21203/rs.3.rs-5515414/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5515414/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground: \u003c/strong\u003eAlthough thymic enlargement is a common and physiological finding of neonates and infants, symptomatic hyperplasia is a very rare condition.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCase presentation:\u003c/strong\u003e We report a 21-hour male neonate who presented with fast and noisy breathing and failure to suck for 12 hours duration. He had signs of respiratory distress and was initially started on treatment for early-onset sepsis without any improvement. Later imaging showed a thymic enlargement which was then successfully treated with steroids.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion: \u003c/strong\u003eSymptomatic thymic hyperplasia is an uncommon condition in the neonatal period. Steroids can be effective in the treatment of thymic hyperplasia help shrink the enlarged thymus and avoid unnecessary surgery.\u003c/p\u003e","manuscriptTitle":"Thymic hyperplasia presenting with respiratory distress in a male newborn: A case report","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-01-20 17:46:56","doi":"10.21203/rs.3.rs-5515414/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":"cc7c08c4-74e5-46cc-8e29-1d96728693d3","owner":[],"postedDate":"January 20th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-01-20T17:46:56+00:00","versionOfRecord":[],"versionCreatedAt":"2025-01-20 17:46:56","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5515414","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5515414","identity":"rs-5515414","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}