Renal angiomyolipoma, a benign hamartoma composed of varying amounts of vascular, smooth muscle and fat elements, occurs in either solitary or multifocal fashion. If the abnormal vascular elements predominate or if the tumor is of significant size, patients may become clinically symptomatic and thus require intervention. Symptoms may include hematuria, flank pain, fever and hypotension. Causes for these symptoms relate to tumor size, spontaneous retroperitoneal hemorrhage, erosion into the renal collecting system and renal infarction. Management involves nephron sparing procedures such as selective transcatheter embolization and tumor resection, with the former more frequently employed. In this exhibit we illustrate and discuss, with clinical and imaging examples, the current techniques for treating symptomatic renal angiomyolipomas.
Materials & Methods
We present the clinical and imaging findings in representative cases of symptomatic renal angiomyolipoma that were managed with transcatheter embolization. The techniques of transcatheter treatment of these lesions are discussed, as are the available embolic agents and their efficacy. The role of prophylactic embolization for asymptomatic tumors and the size criteria for treatment are also examined. The anatomic considerations, treatment success rates, degree of renal preservation, prevention of tumor recurrence and resolution of clinical symptoms, as well as the complications, surveillance imaging and re-intervention strategies are illustrated and discussed.
Teaching Points
Renal angiomyolipomas may become clinically symptomatic for various reasons. The most severe potential complication in a symptomatic lesion is life threatening spontaneous retroperitoneal hemorrhage. Larger tumors have a higher risk of bleeding and thus may be prophylactically managed, even if asymptomatic. Selective transcatheter tumor embolization, with preservation of the normal renal parenchyma, is the preferred treatment for both symptomatic and asymptomatic lesions. Various embolic agents may be used, some of which are more efficacious than others. Post-procedural surveillance imaging is mandatory, as re-intervention is necessary in some patients.
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