Papillary Renal Cell Carcinoma
Definition
- Carcinoma of the kidney with a predominantly papillary growth pattern
Covered Separately (as discrete entities)
Diagnostic Criteria
- Predominantly papillary pattern
- May have tubular areas
- Papillae have fibrovascular cores
- May be intracystic
- Rare cases of apparent solid pattern
- Formed by collapsed tubules and papillae
- Two types, have been defined by the types of cells lining papillae and tubules
- We do not routinely classify papillary carcinomas according to type
- In our experience, many cases show a mixed pattern or do not clearly conform to either of these types
- Nevertheless, familial cases associated with MET mutations tend to show a type 1 morphology whereas those associated with fumarate hydratase mutations tend to show a type 2 morphology
- Type 1 is lined by small cells with clear to basophilic cytoplasm
- Single layer of small oval nuclei
- Inconspicuous nucleoli
- Frequent findings
- Foamy macrophages and/or edema in papillary cores
- Psammoma bodies and calcium oxalate crystals
- Glomeruloid papillae
- Most cases low grade (1 or 2)and low stage
- Single layer of small oval nuclei
- Type 2 is lined by large cells with abundant eosinophilic cytoplasm
- If cytoplasm is extensively granular, consider papillary oncocytoma, see Differential Diagnosis
- Nuclei frequently pseudostratified or apical
- Large spherical nuclei
- Prominent nucleoli
- Macrophages, edema, psammoma bodies, glomeruloid papillae infrequent
- Most cases high grade (3), many higher stage
- We do not routinely classify papillary carcinomas according to type
- Papillary carcinoma with low grade spindle cell features has been described (Argani)
- Predominantly solid
- 4 of 5 reported cases had papillary areas
- All appear to be Type 1
- Nuclear grade 2
- Lacks mucinous stroma of mucinous tubular and spindle cell carcinoma
- May be distinguishable only by FISH for trisomy 7 or 17
- Predominantly solid
- If under 0.5 cm and grade 1 or 2, designate as papillary adenoma
John P Higgins MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting:: January 24, 2011
