title: Cytokeratin-containing globular filamentous bodies in renal oncocytoma.
abstract: Eighty-four cortical neoplasms were studied for cytokeratin and vimentin expression by immunohistochemistry and for intermediate filament aggregates by electron microscopy. Twenty oncocytomas expressed cytokeratin, 16 in a distinctive punctate pattern. These same 16 tumors also contained small globular filamentous bodies (GFB) by electron microscopy. The GFB were characterized by a matrix of intermediate-sized filaments with incorporation of diverse cell organelles such as endoplasmic reticulum, lysosomes, mitochondria, and lipid. The GFB were not within a unit membrane. Although 11 of 64 carcinomas also contained intermediate filament aggregates, only 2 of these solely expressed cytokeratin, and this was restricted to a few cells in small foci. Small GFB were also present in 5 carcinomas by electron microscopy. Three mixed clear and granular cell carcinomas contained only rare cells, whereas 2 sarcomatoid carcinomas, both of rhabdoid cell phenotype, contained numerous GFB that coexpressed vimentin and cytokeratin. Cytokeratin-containing GFB are common in oncocytomas but are uncommon in carcinoma, and, when numerous, may provide a diagnostically useful immunohistochemical feature with which to distinguish oncocytoma from its carcinoma congeners.
authors.affiliation: Department of Pathology, University of Iowa Hospitals and Clinics, Iowa City 52240.
authors.forename: S M
authors.initials: SM
authors.lastname: Bonsib
authors.forename: C
authors.initials: C
authors.lastname: Bray
mesh_terms: D000236:Adenoma / Q000737:chemistry / Q000473:pathology / Q000648:ultrastructure*; D006801:Humans; D007150:Immunohistochemistry; D002479:Inclusion Bodies / Q000737:chemistry* / Q000648:ultrastructure*; D007633:Keratins / Q000032:analysis*; D007680:Kidney Neoplasms / Q000737:chemistry / Q000473:pathology / Q000648:ultrastructure*; D008854:Microscopy, Electron; D015388:Organelles / Q000648:ultrastructure; D014746:Vimentin / Q000032:analysis
chemical_list: D014746:Vimentin; D007633:Keratins