Germinomas are rare malignant primary brain tumors thought to be arising from primordial germ cells of the yolk sac endoderm. They form part of the spectrum of germ cell tumors (GCTs) and are the commonest type of GCT in the central nervous system (CNS). in the CNS the histopathological appearances are termed germinoma and account for approximately 60% of all primary intracranial GCTs. Intracranial GCTs are histopathologically identical to their gonadal counterparts with a testicular primary being referred to as a seminoma and an ovarian primary as a dysgerminoma.
Germinomas account for 1–3% of all intracranial neoplasms and commonly arise in midline structures adjacent to the third ventricle. The most common regions involved are the pineal (∼45%) and suprasellar (∼35%) areas. In around 15% of cases concurrent lesions are detected in both the pineal gland and the suprasellar area or very rarely the basal ganglia or the brainstem. These tumors