title: Extrarenal rhabdoid tumors of soft tissue: clinicopathological and molecular genetic review and distinction from other soft-tissue sarcomas with rhabdoid features.
abstract: Malignant rhabdoid tumor (MRT) of the soft tissue is a rare and highly aggressive tumor that occurs in infancy or childhood. It predominantly involves a deep axial location such as the neck or paraspinal region. Microscopically, the tumor is composed of a diffuse proliferation of rounded or polygonal cells with eccentric nuclei, prominent nucleoli and glassy eosinophilic cytoplasm containing hyaline-like inclusion bodies, arranged in sheets and nests. These characteristic 'rhabdoid cells' are also present in certain soft-tissue sarcomas such as synovial sarcoma, extraskeletal myxoid chondrosarcoma and leiomyosarcoma. The existence of rhabdoid cells in these other sarcomas is correlated with a worse prognosis for the patients. Cytogenetic and molecular analyses have shown abnormalities in the long arm of chromosome 22 and alteration of the hSNF5/INI1 (SMARCB1) gene in renal, extrarenal and intracranial MRT. This gene alteration has been considered to be a specific molecular event in MRT, but a recent study has also demonstrated frequent alteration of this gene in proximal-type epithelioid sarcoma (ES). Both MRT of soft tissue and proximal-type ES show immunoreactivity for vimentin, cytokeratin and epithelial membrane antigen. The tumor cells of proximal-type ES are also occasionally positive for CD34 and beta-catenin, whereas MRT of soft tissue has no immunoreaction for these markers. Detailed clinicopathological and immunohistochemical evaluations are necessary to distinguish MRT of soft tissue from proximal-type ES, because these tumors demonstrated a similar morphology and the same gene alteration.
authors.affiliation: Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan. oda@surgpath.med.kyushu-u.ac.jp
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Oda
authors.forename: Masazumi
authors.initials: M
authors.lastname: Tsuneyoshi
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D002868:Chromosomal Proteins, Non-Histone; D003582:Cytogenetics; D004268:DNA-Binding Proteins / Q000032:analysis / Q000235:genetics; D003937:Diagnosis, Differential; D006801:Humans; D007223:Infant; D008967:Molecular Biology; D009154:Mutation; D018335:Rhabdoid Tumor / Q000737:chemistry / Q000235:genetics / Q000473:pathology*; D000071796:SMARCB1 Protein; D012509:Sarcoma / Q000737:chemistry / Q000235:genetics / Q000473:pathology*; D012983:Soft Tissue Neoplasms / Q000737:chemistry / Q000235:genetics / Q000473:pathology*; D014157:Transcription Factors / Q000032:analysis / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D000071796:SMARCB1 Protein; C513266:SMARCB1 protein, human; D014157:Transcription Factors