title: Chromophobe renal cell carcinoma with liposarcomatous dedifferentiation - report of a unique case.
abstract: Sarcomatous transformation of chromophobe renal cell carcinoma (CRCC) is a well recognized phenomenon. Of the published cases with sarcomatous transformation of CRCC, none have shown liposarcomatous differentiation. Out of a cohort of 250 cases of CRCC, 19 (7.6%) showed sarcomatous differentiation. In one case (female, age 46 years), the sarcomatous component of the tumor displayed histological features of a pleomorphic liposar-coma. Light microscopic examination revealed a biphasic pattern with a chromophobe renal cell carcinoma(CRCC) and a high-grade sarcomatous component containing large pleomorphic lipoblasts. In several areas both components were intermingled. The conventional CRCC component showed classic histological features with calcifications, medium-sized polygonal cells arranged in solid-alveolar structures with raisinoid nuclei, pale-eosinophilic flocculent cytoplasm with perinuclear haloes. In addition, a microcystic-adenomatous component had luminal spaces filled with erythrocytes. The CRCC was positive with Hale's colloidal iron-stain whereas the sarcomatous component was negative. The CRCC component was diffusely positive for cytokeratin 7, parvalbumin and racemase but negative for cy-tokeratin 20, vimentin, CD10, carboanhydrase IX and S100-protein. The pleomorphic liposarcomatous component displayed immunereactivity for CD10, vimentin, racemase and focally for carboanhydrase IX. The proliferative activity (Mib-1/Ki-67) was 5% in the CRCC and 30% in the pleomorphic liposarcomatous component. No immunereactivity for MDM2 or CDK4 was detected.This is the first reported case of a sarcomatoid CRCC where the sarcomatous component displayed features of a pleomorphic liposarcoma. The patient died from widespread metastatic disease 12 months after nephrectomy.
authors.affiliation: Department of Pathology, National University Hospital System, Singapore 119074. fredrikpetersson@live.se
authors.forename: Fredrik
authors.initials: F
authors.lastname: Petersson
authors.forename: Michal
authors.initials: M
authors.lastname: Michal
authors.forename: Marcello
authors.initials: M
authors.lastname: Franco
authors.forename: Ondrej
authors.initials: O
authors.lastname: Hes
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D002292:Carcinoma, Renal Cell / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007680:Kidney Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D008080:Liposarcoma / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D008875:Middle Aged; D009392:Nephrectomy
chemical_list: D014408:Biomarkers, Tumor