Long-term volume reduction in renal angiomyolipomas embolized by gelatin sponge particles with or without supplementary microcoil embolization

OBJECTIVE: To examine the effect of supplementary microcoil embolization on the long-term progression of angiomyolipomas embolized using gelatin sponge particles (GSPs). METHODS: This retrospective study included 29 unruptured angiomyolipomas in 25 patients, treated by complete embolization and radiological follow-up for ≥3 years. Embolization was performed using GSPs and supplementary microcoils. Supplementary microcoil embolization affecting >90% of the tumor vasculature was defined as microcoil embolization. Tumor volumes pre- and post-embolization were measured by computed tomography or magnetic resonance imaging. RESULTS: Eleven tumors received supplementary microcoil embolization and 18 tumors did not. Relative tumor reduction at >3 years post-embolization was significantly greater in tumors with supplementary microcoil embolization compared with tumors without microcoil embolization (81% ± 8% vs. 55% ± 29%). Fourteen tumors tended to show volume regrowth and the volumes of the remaining 15 tumors continued to decline. Tumors without supplementary microcoil embolization were more likely to show volume regrowth during follow-up than tumors with supplementary microcoil embolization (78% vs. 0%, respectively). CONCLUSIONS: When using a combination of GSPs and microcoils, supplementary microcoil embolization should be carried out to ensure maximum long-term reduction in tumor volume in patients with angiomyolipomas.