Benign renal tumors detected among healthy adults by abdominal ultrasonography.

Renal ultrasonography was performed on 17,941 healthy adults without any signs suggestive of urinary tract malignancies. Diffusely hyperechoic renal masses indicative of angiomyolipoma were found in 41 (0.23%) of them and those with echogenic image suggestive of renal cell carcinoma in 45 (0.25%). Final diagnosis of the former group included 24 angiomyolipoma, 1 renal cell carcinoma, 9 calculus and 7 normal variants. The latter group included 19 renal cell carcinomas, 1 leiomyoma, 1 cavernous hemangioma and 24 normal variants or cysts. In total, 24 (0.13%) angiomyolipomas, 20 (0.11%) renal cell carcinomas, 1 leiomyoma, and 1 cavernous hemangioma were discovered. The results indicate that asymptomatic benign renal tumors mainly consisting of angiomyolipoma are not uncommon.