Metanephric adenomas are usually positive for WT1 (diffuse nuclear; shown here) and CD57. They are usually negative for CK7. Papillary renal cell carcinomas are usually positive for CK7 and negative for WT1 and CD57. Case courtesy of: Dr. Abdul Haleem, Dept. of Pathology, King Abdul Aziz Hospital, Al-Ahsa, Saudi Arabia.