Papillary renal cell carcinoma: clinical implication of DNA content analysis

Papillary renal cell carcinoma is considered a less-aggressive histomorphologic variant of renal cell carcinoma. We investigated the clinicopathologic features and the DNA ploidy pattern in 22 papillary renal cell carcinoma cases and correlated the findings to the patients' length of survival. In this study the demographic data were similar to those of previously published series. Histologically, two neoplasms were Fuhrman's nuclear grade 1, eight were nuclear grade 2, 11 were nuclear grade 3, and one was nuclear grade 4. Six tumors were stage I, three were stage II, five were stage III, and eight were stage IV. With a mean follow-up period of 42 months, eight patients died of disease and 14 were alive and well. DNA aneuploidy was found in 50% of the neoplasms and was frequently associated with high tumor nuclear grade, high tumor stage, and poor prognosis. Conversely, DNA diploidy was preponderantly noted in neoplasms with low tumor nuclear grade and stage, and none of the patients died of their disease. A statistically significant difference between DNA ploidy/tumor stage and patient outcome was obtained. No significant correlation between DNA ploidy and nuclear grade was observed. Our results suggest that DNA content measurements may assist in evaluating the clinical outcome of this neoplasm. Moreover, they indicate that papillary renal cell carcinomas manifest clinicopathologic, DNA content, and biologic characteristics akin to those of nonpapillary variants.