Papillary renal cell carcinoma: clinicopathological characteristics and evaluation of prognosis in 42 patients

OBJECTIVE: To determine the clinicopathological characteristics of histologically defined papillary renal cell carcinoma (RCC) in relation to prognosis. PATIENTS AND METHODS: In total, 768 patients with RCC underwent nephrectomy at our university hospital between 1957 and 1995. RCC was classified into clear-cell carcinoma in 689 patients (89.7%, no follow-up in 14), chromophobe cell carcinoma in 36 (4.7%, no follow-up in two) and papillary RCC in 43 (5.6%, no follow-up in one). In the present study, the 42 patients with papillary RCC who underwent nephrectomy and were followed up were those in whom the clinicopathological features of the papillary RCC were assessed. Factors assessed were the presence or absence of foam-cell infiltration, occurrence of bleeding and/or necrosis, presence or absence of a pseudocapsule, mixed occurrence with clear-cell carcinoma, presence or absence of solid variants, cytoplasmic appearance (basophilic vs eosinophilic cells), stage, nuclear grade of malignancy, and angiographic appearance in relation to prognosis. The prognosis was also compared among patients with clear-cell, chromophobe cell and papillary RCC. RESULTS: The prognosis was significantly better in patients with foam-cell infiltration (P=0.03), with a pseudocapsule (P=0.07), with no solid variants (P=0.001) and with basophilic cells (P<0.001). There were also significant differences in survival between patients with low-stage (1+2) and high-stage (3+4) disease (P=0.003), and among grades 1-3 (grade 1 vs 2, P=0.05; grade 1 vs 3, P<0.001, grade 2 vs 3, P=0.006). Furthermore, the prognosis in patients with papillary RCC was worse than in those with chromophobe cell carcinoma (P=0.02), but there was no significant difference in survival between patients with papillary RCC and those with clear-cell carcinoma. CONCLUSION: The clinicopathological features (e.g. the presence or absence of foam cells, of a pseudocapsule and of solid variants, cytoplasmic appearance, and the stage and nuclear grade of malignancy) are important prognostic factors for patients with papillary RCC. Furthermore, the prognosis in patients with papillary RCC is similar to those with clear-cell carcinoma.