To distinguish common epithelial tumors arising in the kidney may have significant implications, in terms of molecular ontogeny and prognosis. It is important to investigate the distribution of immunoexpression of commonly used markers among renal neoplasms and to develop a useful panel as an adjunct to histologic examination, which could lead to the accurate diagnosis of both primary and metastatic tumors. Immunohistochemical stains for CD10, vimentin (VIM), E-cadherin (E-CD), cytokeratins (CK) 7, 8, 19, and 20, high molecular weight keratin (HCK), and peanut lectin agglutinin (PL) (Arachis hypogaea) were performed on 45 (96 for CK7, CK20) conventional (CC), 20 papillary (PC), and 6 (24 for CK7, CK20) chromophobe renal carcinomas (CPC); 12 oncocytomas (OC); 5 collecting duct carcinomas (CDC), and 25 urothelial carcinomas of the renal pelvis (UC). Reactivity for CD 10 was evaluated on the basis of the presence of cell surface staining; that for all CKs, cytoplasmic/membranous staining; and that for PL, luminal staining. Both CD 10 and VIM were predominantly expressed in CC and PC; E-CD in CPC, OC, and UC; CK7 in PC, CPC, and UC; CK8 and CK19 in CDC and UC; CK20 in UC; HCK in CDC and UC; and PL in CDC. CC and OC were predominantly CK7-/CK20-; PC, CK7+/20-; CPC, CK7+/CK20- or CK7-/CK20-; and UC, CK7+/CK20- or CK7+/CK20+. CDC showed slight predominance of CK7-/20- over CK7+/CK20-. CC was most frequently CD10+/CK7-/HCK-/PL-; PC, CDIO+/CK7+/HCK-/PL-; CPC, CD 10-/CK7+/HCK-/PL-; OC, CD 10-/CK7-/HCK-/PL-; CDC, CD10-/CK7+/HCK-/PL+ or CD10-/CK7-/ HCK+/PL+; and UC, CD10-/CK7+/HCK+/PL-. Discriminant analysis suggested that CD10/CK7/HCK/PL may be a useful primary immunopanel for distinguishing among CC, PC, CDC, and UC.