Atypical teratoid rhabdoid tumor located in the pineal region following prophylactic irradiation for acute lymphoblastic leukemia.

Atypical teratoid rhabdoid tumor (AT/RT) is a rare entity. In the central nervous system, AT/RT generally arises from the posterior fossa of infants and behaves aggressively. AT/RT is reported to arise from the infratentorial region (63%) and other sites, such as the suprasellar region, cerebellopontine angle, and spinal cord. The pineal region is rare (6%) as a site of origin. Radiation-induced brain tumors are well known. In this report, we present a case of a pineal region tumor causing acute hydrocephalus that could be pathologically diagnosed as AT/RT following prophylactic cranial irradiation for acute lymphoblastic leukemia.