# Bifocal β-hCG-secreting CNS Germinoma in a 13-Year-Old Boy: Clinical–Biochemical Pubertal Discordance and Long-Term Outcome

## TL;DR

A 13-year-old boy with a rare brain tumor showed signs of early puberty due to a hormone-secreting tumor, which was successfully treated with a combination of therapies.

## Contribution

This case highlights the importance of β-hCG testing and neuroimaging in diagnosing rare CNS germinomas presenting with pubertal discordance.

## Key findings

- β-hCG-secreting germinoma can induce gonadotropin-independent puberty in pediatric patients.
- CSF sampling via EVD is a safe alternative when lumbar puncture is not feasible.
- Coordinated oncologic and endocrine care leads to durable disease control in such cases.

## Abstract

Intracranial germ cell tumors (GCTs) are rare in the pediatric population. They are classified as germinoma and nongerminomatous and may secrete specific proteins such as β subunit of human chorionic gonadotropin (β-hCG) and alpha-fetoprotein (AFP). When secreting β-hCG, they may induce gonadotropin-independent puberty (GIP), a clinical diagnostic clue that can precede neuroimaging findings.

A 13-year-old boy presented with a first generalized tonic–clonic seizure after six months of headaches, vomiting, polyuria, and polydipsia. Examination showed pubertal penile length with peripubertal testes. Laboratory assessment revealed panhypopituitarism with suppressed gonadotropins and elevated testosterone. Brain magnetic resonance imaging (MRI) demonstrated bifocal lesions (pineal and suprasellar) with obstructive hydrocephalus. Cerebrospinal fluid (CSF) sample obtained via temporary external ventricular drain (EVD) showed a normal cytology, confirming a β-hCG-secreting germinoma. The patient achieved remission after chemotherapy, neurosurgical resection, and cranial radiotherapy. He developed a posterior medulla relapse successfully salvaged with gemcitabine–paclitaxel–oxaliplatin, high-dose etoposide–thiotepa with autologous stem-cell transplantation, and craniospinal irradiation.

Discordant clinical and biochemical puberty (penile enlargement with small testes and high testosterone with suppressed gonadotropins) should prompt β-hCG testing and targeted neuroimaging for suspected central nervous system GCTs. When raised intracranial pressure precludes lumbar puncture, CSF sampling via EVD is a safe alternative. Coordinated oncologic–endocrine care supports durable disease control with tailored long-term hormonal follow-up.