Metachronous Intracranial Germinoma Recurrence After Long-Term Remission: A Case Report.

Intracranial germinomas are rare central nervous system neoplasms. Their diagnosis relies on clinicoradiological correlation and tumor marker assessment. Radiotherapy alone often achieves complete remission; however, late recurrences in atypical locations have been reported, underscoring the importance of timely diagnosis, appropriate treatment, and long-term surveillance in patients with intracranial germinoma. We report the case of a 22-year-old man who presented with severe pulsatile headache, photophobia, phonophobia, vomiting, bilateral thigh weakness, and urinary incontinence. Computed tomography revealed a pineal tumor with obstructive hydrocephalus, prompting ventriculoperitoneal shunt placement. Tumor markers were elevated (serum beta human chorionic gonadotropin (β-hCG) 18.46 mIU/mL, cerebrospinal fluid (CSF) β-hCG 16.8 mIU/mL, serum alpha-fetoprotein (AFP) 2.71 ng/mL, and CSF AFP 0.2 ng/mL). Radiotherapy achieved complete remission; however, the patient subsequently developed radiation-induced hypopituitarism requiring lifelong hormone replacement therapy. Thirteen years after the initial diagnosis, surveillance imaging demonstrated periventricular and callosal enhancement associated with mildly elevated tumor markers. Biopsy revealed OCT4 and CD117 positivity, confirming a new germinoma interpreted as a metachronous neoplasm. This case highlights the value of comprehensive diagnostic evaluation and emphasizes the need for long-term, multidisciplinary follow-up due to the risk of late sequelae and atypical recurrences in patients with intracranial germinoma.