OBJECTIVETo study the diagnosis and management of renal angiomyolipoma (RAML), and to identify risk factors affecting spontaneous angiomyolipoma rupture.

METHODSThe data of 68 patients with RAML from 1989 to 2002 were retrospectively reviewed. These patients were divided in two groups on the basis of tumor size, 35 patients in group A ( 4 cm).

RESULTSSeven patients were identified by image-guided percutaneous biopsy, and no major complications was noted. Sixteen patients with RAML were examined with angiography and 9 of 16 patients had got spontaneous rupture. 41.2% of patients were symptomatic, 4 cases (11.4%) in group A and 24 (72.7%) cases in group B (P < 0.01). There were significant differences in mean tumor size (11.6 cm +/- 5.1 cm vs 5.3 cm +/- 2.9 cm, P < 0.01) and mean aneurysm size (13.6 mm +/- 5.8 mm vs 2.6 mm +/- 3.0 mm, P < 0.01) between 9 cases of the ruptured tumor and 59 cases of unruptured tumor, 9 cases of the ruptured and 7 cases of unruptured tumor with angiography, respectively. Treatment consisted of conservative observation in 10 patients (no radiographic changes during the follow-up of 2 - 7 years); partial nephrectomy in 14 patients, tumor enucleation in 30 patients, total nephrectomy in 14 and posterior laparoscopic nephrectomy in 3 (no recurrence and complication correlation to operation during the follow-up of 2 - 144 months).

CONCLUSIONSIt is an important role that percutaneous biopsy guided by ultrasonography or computerized tomography performs in managing suspicious and/or indeterminate RAML. A higher probability of rupture is related to tumor and/or aneurysms size. Nephron-sparing surgery is the first choice for surgical treatment of RAML.