Typical histology | Expected immunoprofile | Recommendation | |
---|---|---|---|
Papillary carcinoma | Papillary architecture, but tubulopapillary, glomeruloid, and dense papillary simulating solid; single layer of cuboidal cells; foamy macrophages and psammoma bodies | CK7+ AMARC+ | - no IHC needed if typical morphology - consider differential with papillary adenoma and metanephric adenoma |
Papillary adenoma | Similar to papillary RCC type 1; low grade nuclei, no fibrous capsule, ≤15 mm | CK7+ AMARC+ | - no IHC needed if typical morphology |
Mucinous tubular and spindle cell carcinoma | Small tubules lined by cuboidal cells, bland spindle cell component, variable amount of mucinous / myxoid stroma | CK7+ AMARC+ | - no IHC needed if typical morphology |
Metanephric adenoma | Small tubules that may simulate solid areas; glomeruloid and/or papillary formations | WT1 + CD56 + BRAF VE1 + CK7- AMARC - | - rule out papillary carcinoma |