Absence of expression of SMARCB1/INI1 in malignant rhabdoid tumors of the central nervous system, kidneys and soft tissue: an immunohistochemical study with implications for diagnosis.

Malignant rhabdoid tumors are high-grade neoplasms of the central nervous system (CNS), kidneys and soft tissue that usually occur in children. The histologic diagnosis of malignant rhabdoid tumor depends on identification of characteristic rhabdoid cells-large cells with eccentrically located nuclei and abundant, eosinophilic cytoplasm-and immunohistochemistry with antibodies to vimentin, keratin and epithelial membrane antigen. In most malignant rhabdoid tumors, the SMARCB1/INI1 gene, located in chromosome band 22q11.