Tubular dysplasia and carcinoma in situ: precursors of renal cell carcinoma

Abstract

Objectives. To identify the dysplastic changes in tubules adjacent to or remote from renal cell carcinoma (RCC) and to assess proliferating cell nuclear antigen (PCNA) expression of normal tubule and carcinoma cells. Methods. The study analyzed 62 kidneys with RCC that were removed by radical nephrectomy. Pathologic sections were stained with hematoxylin-eosin and evaluated for the presence of dysplasia. Sections that contained dysplasia were then stained by the avidin-biotin immunoperoxidase technique after epitope retrieval for PCNA. Results. Dysplastic changes in normal kidney were identified in 14 cases (23%). Dysplastic changes were adjacent to the tumor in 10 cases. Dysplasia was adjacent to the tumor and diffuse in 6 cases (3 clear cell [CRCC], 2 chromophobe [ChRCC], 1 sarcomatoid RCC [SRCC]), adjacent to the tumor and focal in 4 cases (2 CRCC, 1 papillary RCC, 1 SRCC), remote and focal in 3 cases (1 granular RCC, 1 ChRCC, 1 SRCC), and remote and diffuse in 1 case (CRCC). The lesions represented a focus that could be defined as carcinoma in situ in 3 cases. PCNA immunostaining in dysplastic epithelia was more intense than that in normal tubules and was as intense or even more intense than that in carcinoma cells. Conclusions. Dysplasia of tubular epithelium is probably a biologic precursor of at least some RCC. Tubular dysplasia warrants further study as an important phase that will provide new insights into the pathogenesis, biologic behavior, and natural history of RCC. Its impact on the surgical management of small unilateral RCC needs to be investigated.