Prevalence of sporadic renal angiomyolipoma: a retrospective analysis of 61,389 in- and out-patients.

PURPOSE: To calculate the prevalence, localization, and growth of sporadic angiomyolipomas and to identify the predominant sex in the largest patient population reviewed to date. METHODS: Abdominal ultrasound analyses of 61,389 patients (49.7% women; 50.3% men) were consecutively collected using a PC-based, standardized documentation system from September 1999 to December 2012. The present study evaluates and presents this data. RESULTS: The population studied includes 270 cases of sporadic angiomyolipoma (184 females; 86 males). This represents an overall prevalence of 0.44%, with 0.60% in the female and 0.28% in the male subpopulations. Mean tumor size was 10.8 ± 5.8 mm. Fifty-seven percent of cases involved the right kidney and 43.0% the left kidney. Only 14 of the 270 patients presented with multiple angiomyolipomas, four of which were bilateral. Sixty-one cases were followed over a mean period of 25 months (range: 1-105 months) and showed no significant increase in tumor size during the period of observation. CONCLUSION: The analysis of 61,389 patients revealed a higher prevalence of sporadic angiomyolipoma than previously observed in smaller studies. There was a significantly higher prevalence in females than in males. Multiple and bilateral angiomyolipomas were rare, and tumor growth was marginal.