Embolization of Renal Angiomyolipomata in Patients With Tuberous Sclerosis Complex

Background: Renal angiomyolipomata can reduce renal reserve and lead to renal insufficiency and failure. Angiomyolipomata often have abnormal vasculature, with aneurysms that can hemorrhage. Treatment of angiomyolipomata greater than 4 cm in diameter is suggested to decrease the risk for hemorrhage. Nephron-sparing procedures are critical in patients because of their limited renal reserve. Embolization has been used to treat these tumors, but there are limited studies examining efficacy. Our study examines the efficacy of selective embolization in decreasing tumor burden, preventing hemorrhage, and preserving renal function. Methods: We conducted a retrospective study of 16 patients with 20 angiomyolipomata on 18 kidneys who underwent 18 transcatheter transarterial embolization procedures. Aneurysm number and size were documented and tumor volumes were measured before and after embolization. Preprocedure and follow-up renal function also were measured. Changes in angiomyolipoma volume and kidney function were assessed for significance by using paired t-test. Results: Before embolization, 7 angiomyolipomata had more than 5 aneurysms, 9 had 1 to 5 aneurysms, and 4 had no aneurysms, but showed tortuous dysmorphic arteries. Mean aneurysm size was 5 mm. In patients available for follow-up, 15 of 16 tumors had decreased in volume (mean decrease, 56.1%; P = 0.001). At an average of 40 months' follow-up, there have been no subsequent hemorrhages. Patients' decline in renal function was not significantly different from that expected because of the natural course of the disease. Conclusion: Selective embolization decreases tumor size, prevents hemorrhage, and preserves kidney function in patients with tuberous sclerosis with renal angiomyolipomata.