Atypical teratoid rhabdoid tumors (ATRT) is a CNS embryonal tumor composed of histologically variable tumor cells with polyphenotypic differentiation into neuroectodermal, epithelial, and mesenchymal lineages and alterations involving SMARCB1 (INI1, most common) or SMARCA4 (BRG1). Rhabdoid cells are a frequent finding. ATRT is very rare in adults and accounts for more than 10% of CNS tumors in infants. Three molecular groups of ATRT have emerged through molecular analysis: ATRT-TYR, ATRT-SHH, and ATRT-MYC, with associated clinical, genetic, and epigenetic characteristics.
