Atypical teratoid rhabdoid tumor

An atypical teratoid rhabdoid tumor, abbreviated AT/RT, is a rare tumor usually diagnosed in childhood. It is most often a brain tumor but can arise anywhere in the central nervous system, including the spinal cord, and about 60 percent occur in the posterior cranial fossa, particularly the cerebellum. In the United States roughly three children per million, around 30 new cases a year, are diagnosed, about 3 percent of pediatric central nervous system cancers. The tumor was only recognized as a distinct entity in 1996 and was added to the World Health Organization brain tumor classification in 2000 as Grade IV. Its rarity and recent recognition contributed to early misdiagnosis and a historically poor prognosis, though multimodal therapy has since improved reported survival.