title: Monophasic synovial sarcoma of spindle-cell type. Epithelial differentiation as revealed by ultrastructural features, content of prekeratin and binding of peanut agglutinin.
abstract: Monophasic synovial sarcomas of spindle-cell type and fibrosarcomas were studied by electron and immunofluorescence microscopy for their intermediate filament expression and the binding of peanut agglutinin (PNA). In monophasic synovial sarcomas of spindle-cell type (two cases), frequent cell-to-cell junctions, irregular cytoplasmic processes, and occasional cytoplasmic, tonofilament-like bundles of intermediate filaments were seen by electron microscopy. These features were absent from fibrosarcomas. Immunohistologically, the monophasic synovial sarcomas showed arrays of prekeratin-positive cells in the midst of the vimentin-positive spindle cells. By double fluorescence microscopy, the prekeratin-positive cells also bound PNA, like the epithelial-like cells of the classical biphasic synovial sarcoma. In contrast to monophasic synovial sarcomas, prekeratin-positive cells and arrays of PNA-binding cells, were not seen by immunofluorescence microscopy in fibrosarcomas (seven cases). Thus the prekeratin-content, the binding of PNA lectin, and certain ultrastructural features suggesting early epithelial differentiation, help to distinguish monophasic synovial sarcomas of spindle-cell type from other spindle cell sarcomas.
mesh_terms: D000328:Adult; D001665:Binding Sites; D003599:Cytoskeleton / Q000648:ultrastructure; D004551:Elbow Joint; D005260:Female; D005354:Fibrosarcoma / Q000032:analysis / Q000648:ultrastructure; D005384:Finger Joint; D006651:Histocytochemistry; D006801:Humans; D007381:Intermediate Filament Proteins / Q000032:analysis; D007592:Joint Diseases / Q000473:pathology*; D007633:Keratins / Q000032:analysis*; D037102:Lectins / Q000032:analysis*; D008297:Male; D008854:Microscopy, Electron; D011498:Protein Precursors / Q000032:analysis*; D013584:Sarcoma, Synovial / Q000032:analysis / Q000648:ultrastructure*; D014746:Vimentin
chemical_list: D007381:Intermediate Filament Proteins; D037102:Lectins; D011498:Protein Precursors; D014746:Vimentin; C004818:prekeratin; D007633:Keratins