Clinicopathologic study of 97 cases of small renal cell carcinomas using DNA flow cytometric analyses

The incidence of small renal cell carcinomas (RCC) has increased recently as diagnostic imaging techniques have improved. The indications for partial nephrectomy for small RCC confined to the kidney are still controversial. Ninety-seven small RCC 2.5 cm or smaller, including incidental, occult, and dialysis associated carcinomas obtained at surgery or autopsy were examined. Various clinicopathologic parameters were assessed and survival was analyzed using the Kaplan-Meir method. Seventy-eight cases were incidental carcinomas. Carcinomas caused death in five cases, four of which had initial signs of metastatic disease. Differences in survival between patients with expansive and invasive (intermediate and infiltrating) growth patterns, solid and other structural patterns, clear and other cell types, grade 1 and higher grades of nuclear atypia, and with and without lymph node metastasis were statistically significant. All surgical cases were alive except one who died of another disease. Poor prognostic factors seen in five fatal autopsy cases included invasive growth pattern, solid structural pattern, spindle cells, grade 3 nuclear atypia, and Bellini duct carcinoma. Small RCC may be treated with partial nephrectomy provided they do not show these features, although there is low risk of recurrence or development of de novo cancer.