Case Report Chromophobe renal cell carcinoma with liposarcomatous dedifferentiation -report of a unique case
Fredrik Petersson, Michal Michal, Marcello Franco, Ondrej Hes
Department of Pathology, National University Hospital System, Singapore; Sikl's Department of Pathology, Charles University, Medical Faculty Hospital, Pilsen, Czech Republic; Departmentt of Pathology, Federal University of Sao Paolo EPM/UNIFESP, Brazil
Received January 25, 2010, accepted April 23, 2010, available online May 5, 2010
Abstract: Sarcomatoid 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 dedifferentiation. 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 liposarcoma. 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 cytokeratin 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 of the tumor displayed features of a pleomorphic liposarcoma. The patient died from widespread metastatic disease 12 months after nephrectomy.(IJCEP1001009).
Address all correspondence to: Fredrik Petersson MD, PhD Department of Pathology, National University Health System, 5 Lower Kent Ridge Road, Singapore 119074. Fax: +6567780671 Phone: +6597714890 E-mail: email@example.com