Endocrine Abstracts

JOINT3867

Introduction: Germinomas are rare intracranial tumors that typically arise in the pineal or suprasellar regions, predominantly affecting adolescents and young adults, with a male predominance. When located in the suprasellar region, they may infiltrate the optic chiasm, leading to visual impairment and endocrine dysfunction. This case highlights the late diagnosis of an optic chiasm germinoma in a 9-year-old girl, emphasizing its late diagnosis and the subsequent development of hypothalamic obesity.

Case Report: A previously healthy 9-year-old girl presented with a rapid weight gain of 23 kg over eight months. Her eating habits had changed abruptly and significantly, and she developed polydipsia-polyuria syndrome (4L/day water intake), which remained unnoticed during the summer months. Upon starting school, a decline in visual acuity was observed. An optic nerve CT was performed, revealing bilateral optic nerve atrophy. Another month was lost investigating a possible neurodegenerative disease. Finally, a cerebral MRI scan revealed a tumor of the optic chiasm, initially suspected to be a craniopharyngioma. The tumor was located suprasellar, intrasellar, and retroclival, infiltrating the optic chiasm and protruding posteriorly into the third ventricle. A subtotal tumor resection was performed via a right pterional approach, and histopathological analysis confirmed the diagnosis of a germinoma, which was actually emerging from the optic chiasm. After surgery, the patient was initiated on hormone replacement therapy with hydrocortisone, levothyroxine, and desmopressin. Metabolically, she presented severe dyslipidemia (high LDL-cholesterol and triglycerides, and low HDL-cholesterol) and hepatic steatosis (as revealed by a FibroScan evaluation: CAP = 339 Db/m and E=3.8 kPa). She was subsequently administered chemotherapy and radiotherapy according to the SIOP CNS GCT II protocol. Her appetite remained voracious despite treatment, but her nutrition was successfully controlled with the involvement of her family. Six months after hydrocortisone substitution, the patient gradually developed a Cushingoid appearance, including truncal obesity, moon face, and extensive purple striae, but no hypertension, despite adequate weight management and controlled corticosteroid dosing. At present, the patient is in remission, with mild visual recovery, and remains under multidisciplinary follow-up involving oncology and endocrinology.

Conclusions: This case highlights the challenges in diagnosing optic chiasm germinomas, especially when visual impairment develops late. Hypothalamic obesity is a significant long-term complication following tumor resection and endocrine dysfunction. Recognizing early symptoms in pediatric patients with rapid weight gain and polydipsia can lead to timelier diagnosis and intervention, definitely improving clinical outcomes, especially visual loss.