title: Chromophobe renal cell carcinoma: clinicopathological study of 7 cases.
abstract: Chromophobe renal cell carcinoma (CRCC) may be grossly and microscopically confused with oncocytoma. It is now believed that many, if not all, of the so-called malignant oncocytomas or oncocytomas with metastases reported in the literature were indeed chromophobe renal cell carcinomas. CRCC is characteristically positive for colloidal iron and shows cytoplasmic microvesicles in electron microscopy. This study of CRCC is thought to be the first one done in Latin America. Of a total of 106 renal epithelial neoplasms, 7 (6.6%) fulfilled the criteria for chromophobe renal cell carcinoma. This frequency in Brazil is similar to that in other parts of the world. There was no difference in age, sex, and race distribution of CRCC compared to usual renal epithelial tumors. Grossly, the CRCC ranged in size from 3.5 to 20 cm (average: 10.2 cm) in greatest dimension. Most frequently, the tumor was brown on the cut surface. The growth pattern showed compact areas in all tumors and, in most of the cases, both clear and eosinophilic cellular subtypes were seen. The electron microscopic findings favor an origin of the microvesicles from outpouchings of the outer membrane of mitochondria. The strong positivity for colloidal iron in spite of the destruction of the cytoplasmic vesicles in paraffin-embedded specimens seems to indicate that the acid mucopolysaccharides are not located inside the microvesicles. By the time of diagnosis, only one case had regional lymph node metastases and this particular case was the only one mixed (associated with the usual renal cell carcinoma). The follow-up examination after nephrectomy showed that prognosis seems to be favorable in CRCC, except when the tumor coexists with the usual renal cell carcinoma.
authors.affiliation: Department of Anatomic pathology, State University of Campinas School of Medicine, UNICAMP, Brazil. athanase@turing.unicamp.br
authors.forename: A
authors.initials: A
authors.lastname: Billis
authors.forename: R B
authors.initials: RB
authors.lastname: Carvalho
authors.forename: E
authors.initials: E
authors.lastname: Magrini
authors.forename: A C
authors.initials: AC
authors.lastname: Mattos
authors.forename: F
authors.initials: F
authors.lastname: Negretti
authors.forename: V R
authors.initials: VR
authors.lastname: Niero
authors.forename: C R
authors.initials: CR
authors.lastname: Nogueira
authors.forename: M C
authors.initials: MC
authors.lastname: Oliveira
authors.forename: H
authors.initials: H
authors.lastname: Piovesan
authors.forename: M J
authors.initials: MJ
authors.lastname: Ramos
authors.forename: A G
authors.initials: AG
authors.lastname: Rocha
authors.forename: C A
authors.initials: CA
authors.lastname: Souza
authors.forename: J T
authors.initials: JT
authors.lastname: Valença Júnior
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology* / Q000648:ultrastructure; D000328:Adult; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000473:pathology* / Q000648:ultrastructure; D005260:Female; D006025:Glycosaminoglycans / Q000032:analysis; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology* / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged
chemical_list: D006025:Glycosaminoglycans