Oncocytoma : RCC
Oncocytomas usually express EMA, pancytokeratin, low molecular weight keratins, CD117, S100 protein and E-cadherin. Vimentin is negative or focally positive. CK7 is usually negative or shows only scattered positive cells which represent entrapped epithelial cells of distal convoluted tubules. CD10 and RCC marker (shown here) are negative.