Beta-hCG-producing thymic teratoma: an uncommon cause of peripheral precocious puberty

Abstract

Introduction: Among the causes of peripheral precocious puberty in men are the beta- human chorionic gonadotropin (β-HCG)-secreting tumors, such as hepatoblastomas, dysgerminomas, choriocarcinomas, and immature teratomas. In pediatrics, the mediastinal teratomas are rare, representing the 7-10% of extragonadal teratomas.

Objective: To describe the case of a patient with peripheral precocious puberty due to a β-HCG -secreting thymic teratoma.

Clinical Case: A seven-years-old schoolboy presents a three-months history of voice changes, gynecomastia, pubic hair appearance, and increased genital volume. In the exams, bone age of nine years, total testosterone 9.33ng/ml (< 0.4ng/ml), dehydroepiandrosterone sulfate (DHEAS), 17-hydroxyprogesterone (17-OHP), and normal adrenocorticotropic hormone (ACTH) test stand out; luteinizing hormone (LH) and follicle stimulating hormone (FSH) with low basal levels, β-HCG 39.5mU/ml (< 2.5 mUI/ml), alpha fetoprotein (α-FP) 11,2ng/ml (0.6-2.0 ng/ml). Imaging study to determine the origin of β-HCG secretion shows normal testicular ultrasound and thoracic, abdominal, and pelvic computerized axial tomography (CAT); brain and sellar resonance without significant findings. The positron emission tomography/computed scan (PET SCAN) shows a tumor image in the anterosuperior mediastinum. The tumor is resected, and the biopsy shows an immature cystic teratoma in the thymus. Post-operatory evolution was satisfactory, with normalization of hormonal levels.

Conclusion: The appearance of a teratoma in a pediatric patient is rare, even more if it is immature, with thymic location and β-HCGsecretor. It is important to consider it within the differential diagnosis facing precocious puberty, as a better way to handle appropriately.