Papillary renal cell carcinoma. Prognostic value of morphological subtypes in a clinicopathologic study of 43 cases.

A series of 43 papillary renal cell carcinomas (PRCCs) were analyzed to investigate the prognostic value of the morphological subtyping (type 1/type 2) proposed by Delahunt and Eble. Twenty-six cases were type 1 (small cuboid cells arranged in single or double layers), 13 cases were type 2 (voluminous eosinophilic cells with irregular pseudostratification pattern), and four cases with oncocytic cells (large eosinophilic cells with round regular nuclei) were distinct from type 2 and grouped apart. All type-1 and oncocytoid-type PRCCs were staged pT1 or pT2, whereas 8/13 type-2 PRCCs were staged pT3 or pT4. Follow-up information (range, 3-113 months; median, 43 months) showed 12 deaths from disease: 2 in the type-1 group,10 in the type-2 group, 0 in the oncocytoid-type group. The Kaplan-Meier analysis showed that pejorative outcome was associated (P<0.001) with high stage (pT3/pT4), high nuclear grade (3/4), morphological type 2, absence of foam cells, and abundant fibrous stroma. The multivariate analysis showed that stage and morphological type were independently associated with survival (P<0.05). These results support the clinical interest of morphological subtyping of PRCCs in the prognosis evaluation of the patients. The four oncocytoid-type PRCCs had a favorable outcome, but additional data are required to evaluate this type of neoplasm.