An Ultra-late Recurrence with Adenoid Cystic Carcinoma-like Malignant Transformation of a Pineal Immature Teratoma after 35 Years: A Case Report

Immature teratomas of the pineal region are a subtype of non-germinomatous germ cell tumors typically associated with early recurrence. Ultra-late recurrence decades after initial treatment is exceedingly uncommon. We report an immature teratoma case in the pineal region that recurred 35 years after subtotal resection and chemoradiotherapy, showing somatic-type malignant transformation into adenoid cystic carcinoma-like adenocarcinoma.