As noted previously, although the ISUP recommendation is to rely predominantly on morphologic features for the differential diagnosis of oncocytoma versus chromophobe renal cell carcinoma, immunohistochemistry for CK7 can be useful in this setting, with more extensive labeling found in chromophobe renal cell carcinoma compared to the scattered individual cell pattern of oncocytoma. The gene discussed is KRT7; the disease is oncocytic adenoma.