Pineal region collision tumor

Collision tumors are exceptionally rare neoplasms characterized by simultaneous presence of two histologically distinct primary brain tumors in the same anatomic location. Their composition can pose a significant therapeutic challenge. Herein, we present a case of a successfully resected pineal region collision tumor composed of a pineocytoma and a pilocytic astrocytoma (PA). A 19-year-old female was admitted with obstructive hydrocephalus due to a pineal gland cyst and underwent surgical excision. Histopathological analysis confirmed a collision tumor comprising pineocytoma and PA. Collision tumors composed of both pineocytoma and PA are extremely rare, with limited cases reported. Their histological architecture presents a diagnostic challenge, requiring meticulous evaluation even by experienced neuropathologists. Given the rarity of such cases, increased awareness of these tumors will facilitate the development of standardized diagnostic criteria and treatment protocols. Multidisciplinary collaboration is essential for optimizing therapeutic strategies tailored to the specific histological composition of collision tumors.