Papillary Renal Cell Carcinoma
Differential Diagnosis
| Papillary Renal Cell Carcinoma |
Conventional Clear Cell Renal Cell Carcinoma with Papillary Foci |
| Papillary pattern usually predominates |
Usually has conventional areas with sheets and clusters of cells with extensive vascular network |
| Fibrovascular cores in papillae |
Lacks fibrovascular cores in papillae |
| Frequent foamy macrophages and psammoma bodies |
Lacks foamy macrophages and psammoma bodies |
| May show intracystic growth pattern |
Does not show intracystic growth |
| CK7 and Racemase/AMACR/P504S usually strong positive |
CK7 and Racemase/AMACR/P504S usually negative to weak/focal |
| Papillary Renal Cell Carcinoma |
Clear Cell Tubulopapillary Renal Cell Carcinoma |
| Clear cell cytoplasm, if present, is focal |
Widespread clear cell cytoplasm, frequently subnuclear/basal |
| Frequently has foamy macrophages, psammoma bodies, stromal hemosiderin |
Lacks foamy macrophages, psammoma bodies, stromal hemosiderin |
| May have high grade nuclear features and necrosis |
Low grade nuclear features, no necrosis |
| CD10 pos, Racemase/AMACR pos |
CD10 neg, Racemase/AMACR neg |
The distinction might be significant since oncocytic papillary carcinomas may have a better prognosis, but more data is needed.
- Mucinous tubular and spindle cell carcinoma may show morphologic and immunophenotypic overlap with papillary renal cell carcinoma (Paner 2006)
- Features that may be shared
- Papillary growth
- Mucin production
- Foam cells
- AMACR expression
- We diagnose borderline cases as papillary carcinoma
- Urologists are much more familiar with that diagnosis
- That diagnosis will probably elicit more extensive followup
- Genetic studies can separate the two but are rarely indicated
| Xp11 Translocation Renal Cell Carcinoma |
Papillary Renal Cell Carcinoma |
| Frequently occurs under age 20 |
Mean age 60 |
| Mixed papillary and clear cell areas |
Clear cell areas focal to absent |
| Voluminous cytoplasm |
Moderately abundant cytoplasm at most |
| Typically high grade nuclear features |
May have any grade nuclear features |
| TPE3 immunostain or FISH positive in >80% |
Lacks Xp11 translocations |
| CK7 & EMA negative to weak |
CK7 & EMA frequently strong positive (but may be negative) |
