Abstract
Primary intracranial teratomas are nongerminomatous germ cell tumors. They are infrequent lesions along the craniospinal axis, with their malignant transformation extremely uncommon. A 50-year-old-male patient presented with one episode of generalized tonic-clonic seizure (GTCS), without any neurological deficit. Radiological imaging revealed a large lesion in the pineal region. He underwent gross total excision of the lesion. Histopathological examination was representative of teratoma with adenocarcinomatous malignant transformation. He underwent adjuvant radiation therapy and had an excellent clinical outcome. The present case highlights the rarity of malignant transformation of the primary intracranial mature teratoma.