Oncocytic Papillary Renal Cell Carcinoma

Definition

Carcinoma of the kidney exhibiting papillary architecture with oncocytic lining cells

Note: it is not presently clear if oncocytic papillary renal cell carcinoma is an independent type of carcinoma or if it represents a subtype of papillary renal cell carcinoma (PRCC)
- Limited data available on behavior
  - Clearly differs from oncocytoma as some cases metastasize
  - May be less aggressive than type 2 PRCC
- About half of reported cases share genetic abnormalities of PRCC
- Immunophenotype reports are variable but generally are similar to PRCC
Predominantly papillary architecture in most cases
- Thin fibrovascular cores
- Rare cases are predominantly solid
  - Recognized based on other features below
- (Note that rare oncocytomas may have focal papillary features, see Differential Diagnosis at left)
Lined by a single layer of oncocytic cells
- Cuboidal to columnar cells
- Abundant granular eosinophilic cytoplasm
- Nuclei generally round and uniform
  - Most are Fuhrman grade 1 or 2
- Nuclei frequently apical
Occasional features
- Clusters of foamy macrophages
- Tumor cell necrosis
- Psammoma bodies
Racemase/AMACR/P504s positive

John P Higgins MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342