Diagnostic utility of vimentin, CD117, cytokeratin-7 and caveolin-1 in differentiation between clear cell renal cell carcinoma, chromophobe renal cell carcinoma and oncocytoma

Overlapping morphological characteristics pose some difficulties in making a proper diagnosis of clear cell renal cell carcinoma (CCRCC), chromophobe renal cell carcinoma (ChRCC), and oncocytoma, on the basis of hematoxylin-eosin-stained tissue sections. Our objective was to find out a fast, reliable panel of immunohistochemical markers for differentiation between them. The study was carried out on 55 selected renal tumor specimens: 36 cases of CCRCC, seven cases of ChRCC, and 12 cases of oncocytoma. The specimens were stained immunohistochemically for vimentin, CD117, cytokeratin (CK)7, and caveolin (Cav)-1. Sensitivity and specificity for each marker were calculated. Vimentin expression was exclusively observed in CCRCC (100%) and negative in ChRCC and oncocytoma. CD117 was absent in CCRCC, but it was strongly expressed in ChRCC (85.5%) and oncocytoma (91.7%), with high sensitivity and specificity. Most CCRCCs and oncocytomas were negative for CK7 (91.7% and 83.3%, respectively), in contrast to ChRCCs, which showed positivity in nearly 86% of the cases. Good sensitivity and specificity were calculated for CK7 in differentiating studied oncocytic tumors. Cav-1 was positive in ∼78% of the CCRCCs and in all ChRCCs, whereas the vast majority of oncocytomas were negative. So the immunoprofile of CCRCC was vimentin+/CD117−/CK7−/Cav-1±, ChRCC was vimentin−/CD117+/CK7+/Cav-1+, and oncocytoma was vimentin−/CD117+/CK7±/Cav-1−. So, by using combination of four markers (vimentin, CD117, CK7, and Cav-1), we achieved excellent sensitivity and specificity for differential diagnosis of CCRCC, ChRCC and oncocytoma.