Atypical teratoid rhabdoid tumor was first reported by Bonnin et al., in 1984. It was incorporated as a separate entity into the WHO classification of tumors of the nervous system, in 1993.

• Atypical teratoid rhabdoid tumor was first reported by Bonnin et al., in 1984.^[1]
• It was incorporated as a separate entity into the WHO classification of tumors of the nervous system, in 1993.
• After the first case of atypical teratoid rhabdoid tumor was reported, it was followed by a series of multiple case reports by Biggs et al. (1987); Ho et al. (1990); Chou and Anderson (1991); Agranovich et al. (1992); and Satoh et al. (1993).
• Previously reported cases of atypical teratoid rhabdoid tumor were often associated with malignant rhabdoid tumors (MRT) of the kidney, which had been identified a decade earlier upon central review of Wilms’ tumor treated in a collaborative group. This group noted that certain patients had tumors with different pathologic features and that these features were associated with significantly worse outcomes.^[1]
• Similarly, atypical teratoid rhabdoid tumor was often categorized with primitive neuroectodermal tumors (PNETs), along with medulloblastoma, due to histologic similarities, but they are now separated from other embryonal tumors by the presence of rhabdoid cells and specific immunohistochemistry.
• Atypical teratoid rhabdoid tumor was only recognized as an entity in 1996 and added to the World Health Organization (WHO) brain tumor classification in 2000 (grade IV).^[2]