What are the indications for prophylactic embolization of renal angiomyolipomas? A review of the current evidence in the literature

Renal angiomyolipomas (AMLs) are benign tumours that may occur sporadically in the general population or in patients with tuberous sclerosis complex. The concern with AMLs is that of retroperitoneal hemorrhage, which can be fatal. Classically the trigger for prophylactic intervention was thought to be an AML diameter of ≥ 4 cm. However, this value is largely based on data from case series and heterogeneous retrospective studies. The PICO (patient, intervention, comparison, outcome) paradigm was used to systematically search the Cochrane database, TRIP database, and PubMed. The quality of evidence in the literature is poor regarding the indications for prophylactic embolization of AMLs (level 4). There are no prospective studies that adequately assess embolization vs other treatment modalities. However, using the available evidence we have produced recommendations for when intervention should be considered. We have also made recommendations regarding the direction of future research. (author)