Oncocytic papillary renal cell carcinoma:a report of 3 cases and review of the literature

Objective: To investigate the clinicopathological characteristics of the oncocytic papillary renal cell carcinoma(OPRCC). Methods: Three cases of OPRCC were investigated by light microscopy, immunohistochemistry, fluorescence in situ hybridization(FISH), and review of the literature. Results: Among 3 cases, 2 cases were male, 1 case was female, and their ages were 41, 45 and 65 years old, respectively. The renal masses in 3 cases were found by medical examination. The masses in 2 cases located in the low pole of the kidney, and 1 case mass located in the middle and high pole of the kidney, the surrounding boundaries between the renal tissue and tumor was clear, and the long diameter of 3 masses were 3.0 cm, 3.5 cm and 4.5 cm, respectively. The cytoplasm of tumor cells were plentiful and eosinophilic, the Fuhrman grades of nuclear were from 2 to 3 grade. Tumor cells arranged in papillary pattern with accumulation of foam cells in the stroma. In 3 cases of tumor cells, vimentin, CD10, AMACR, EMA and CK7 were positive, while TFE3, CD15, CD117, RCC and E-cadherin were negative. FISH test showed that the 7 and 17 chromosomes were amplified in 3 cases of tumor cells. Conclusions: OPRCC is a rarely subtype of renal cell carcinoma, and its immune phenotype and molecular genetics are similar to that of type 1 papillary renal cell carcinoma. The OPRCC should be differentiated with oncocytoma, chromophobe renal cell carcinoma, Xp11.2 translocation of renal cell carcinoma.