Image Description
The immunohistochemical profile of metanephric adenomas (MA) is as follows:
- POSITIVE: WT1 (strong, nuclear), PAX8 (strong, nuclear), CD57 (cytoplasmic/membranous)
- NEGATIVE: CK7 (may be weak, patchy +), AMACR
The combination of CK7-, AMACR-, CD57+ and WT1+ is considered characteristic of metanephric adenoma. Strong diffuse positivity for CK7 and AMACR argues against the diagnosis of MA and favors papillary renal cell carcinoma in the appropriate morphologic context. In this image, the tumor on the left is negative; normal renal tubules on the right are positive for AMACR.