title: Intermediate filaments in eosinophilic cells of epithelioid sarcoma: a light-microscopic, ultrastructural, and electrophoretic study.
abstract: A 41-year-old woman had a mass in her thigh for 5 months. The neoplasm had areas histologically typical of epithelioid sarcoma, but there were also cells with abundant eosinophilic, vacuolated cytoplasm and peripheral, distorted nuclei. These cells resembled signet-ring cells but contained no intracellular mucin. Rather, their cytoplasm was filled with large aggregates of 7-10 nm diameter, nonperiodic filaments, and lipid droplets. Lipid droplets and filaments are common in epithelioid sarcomas, but their presence in sufficient volume to displace the nucleus in a signet-ring fashion has not been described. Electrophoretic analysis of a tumor extract showed that actin was present in insufficient concentration (1-3%) to account for the filamentous aggregates. However, two proteins of 51,000 and 63,000 daltons apparent molecular weight comprised 40-50% of the total protein, suggesting that one or both were the major subunits of the abundant cytoplasmic filaments. Filaments of identical ultrastructural size have been described in a variety of human neoplasms and may be related to a filament characterized in other species and termed vimentin.
mesh_terms: D000199:Actins / Q000032:analysis; D002288:Adenocarcinoma, Mucinous / Q000473:pathology; D000328:Adult; D002467:Cell Nucleus / Q000648:ultrastructure; D003599:Cytoskeleton / Q000648:ultrastructure*; D003951:Diagnostic Errors; D005260:Female; D005266:Femoral Neoplasms / Q000473:pathology; D006801:Humans; D008854:Microscopy, Electron; D009124:Muscle Proteins / Q000032:analysis; D012509:Sarcoma / Q000032:analysis / Q000473:pathology* / Q000648:ultrastructure; D013848:Thigh; D014746:Vimentin
chemical_list: D000199:Actins; D009124:Muscle Proteins; D014746:Vimentin