electron microscopy of two cases revealed a polymorphous population of fibrohistiocytic cells resembling those typical of malignant fibrous histiocytoma , admixed with lymphocytes and plasma cells , but sporadic cells expressed mesothelial properties in the form of sinuous villiform processes , intracytoplasmic neolumina lined by microvilli , and intermediate filaments that were aggregated into tonofilament bundles in some cells .
C0021770
intermediate
C0007634
cells