Background: most of renal neoplasms are of epithelial origin and they are malignant. Renal cell carcinoma (RCC) accounts for approximately 2% of all cancers. The disease resulted in more than 100,000 yearly deaths worldwide. Histologic diagnosis of renal neoplasms is usually straight forward by routine light microscopy. However, immunohistochemistry may be essential in several contexts, including differentiating renal from non- renal neoplasms, differentiating subtypes of primary renal epithelial neoplasms and diagnosing rare types of renal neoplasms or metastatic RCC in biopsy specimens. Aim of the work: multiple therapeutic options tailored to an individual patient are now being offered. In view of these developments, availability of a robust and dependable panel of immunohistochemical stains becomes even more important because pathologists are frequently asked to render diagnosis on limited material. Material and methods: in this study a total number of 50 cases of some types of renal cell tumors were immunohistochemically stained for Napsin A, CD 82 and Cyclin D1. Results: these cases included 18 cases of ccRCC (36%), 16 cases of PRCC (32%), 8 cases of ChRCC (16%) and 8 cases of oncocytoma (16%).Conclusion: we concluded that napsin A may be useful in differentiating between ccRCC and PRCC (particularly type 1 which showed more vacuolated or clear cytoplasm). CD82 may be useful in differentiating between ChRCC, which was CD82 positive and oncocytoma, which was CD82 negative. Cyclin D1 had no significant value in the differentiation of different types of renal epithelial tumors.
Recommendation: we recommended the usage of Napsin A in differentiating between ccRCC and PRCC and CD82 in differentiation between ChRCC and oncocytoma. More studies are needed to evaluate napsin A in differentiating between ChRCC and oncocytoma.