Contemporary Minimally Invasive Treatment Options for Renal Angiomyolipomas

Abstract

Renal angiomyolipomas (AMLs) are benign renal masses that are often asymptomatic and detected incidentally. However, treatment might be necessary in symptomatic presentations or when the mass exceeds 4 cm in size. While the goal of management for renal AMLs is to relieve symptoms and prevent hemorrhage, a priority is renal function preservation, especially given the propensity of these lesions to recur. The traditional treatment for renal AMLs is renal angioembolization or surgical excision of the lesion. With advancements in minimally invasive surgery, several other modalities have now emerged for nephron sparing approaches. These include angioembolization, laparoscopic and percutaneous ablative therapies such as radiofrequency ablation, cryoablation and microwave ablation, and pure or robot-assisted laparoscopic partial nephrectomy. Given the relatively low frequency of renal AMLs requiring treatment, much of the available literature on these minimally invasive approaches is largely extrapolative, based on series on small renal masses, i.e. renal cell carcinoma (RCC). This report is based on a thorough review of the published literature to date on the minimally invasive treatment and outcomes of renal AMLs.

Percutaneous Microwave Ablation of Renal Angiomyolipomas

“…All of the Numerous treatment strategies have been described for AML, including radical nephrectomy, nephron-sparing surgery, renal arterial embolization, cryoablation, RF ablation, and MW ablation [1,2,4]. However, our series is the first to describe the ablation of renal AML with a readily available high-powered gas-cooled MW ablation system.…”

“…Presumably, tissue ischemia causes damage to the tumor parenchyma and is the etiology for the tumor shrinkage that occurs. Embolization is successful in the majority of patients; however, a substantial subset of patients (16-37 %) will require re-treatment after a single session of embolization due to incomplete treatment or revascularization [1,[4][5][6]. In addition, embolization is associated with post-embolization syndrome in up to 85 % of patients, abscess formation in 5 %, and pleural effusion in 3 % [1].…”

“…Surgical removal of AMLs is highly effective in preventing hemorrhage, but is an invasive treatment option for an otherwise benign condition. Consequently, several percutaneous minimally invasive therapies have been described for the treatment of AML, with transarterial embolization currently the most widely applied method [4]. However, embolization as monotherapy has been associated with a need for retreatment or surgical resection in 16-37 % of patients [1,[4][5][6].…”

“…Due to the limitations of current treatment methods, a number of investigators have explored the use of percutaneous ablative techniques such as radiofrequency (RF) ablation, cryoablation, and microwave (MW) ablation for the treatment of AMLs [4]. Heat-based methods such as RF and MW are particularly attractive due to the potential to create both vascular thrombosis and destruction of the tumor parenchyma by thermal coagulation that prevents revascularization.…”

Total nephrectomy with nephron-sparing surgery for a giant bilateral renal angiomyolipoma: A case report

“…Early studies summarized the clinical management of renal AML and established that renal-preserving treatments, including selective angiographic embolization (SAE) and nephron-sparing surgery (NSS), are preferred (5,6). SAE is considered to be an effective and durable treatment for preventing bleeding in large renal AML, particularly for patients with an aneurysm.…”