CIO 2021-16 Clinical Presentations and Endovascular Treatment Options for Renal Angiomyolipomas: Case Series and Review

Purpose: In this educational exhibit, we will review the various endovascular strategies utilized to treat renal angiomyolipomas (AMLs). Although renal AMLs are considered benign neoplasms, they are associated with significant morbidity including possible life-threatening hemorrhage. We will discuss the rationale for selecting a certain embolic agent depending on the clinical presentation of the patient. The most frequently utilized embolic materials include ethanol-ethiodized oil mixture or particles such as polyvinyl alcohol. Coil embolization is generally avoided when embolizing AMLs due to collateral vessel formation. However, coil monotherapy may be considered in cases of ruptured renal AMLs or associated pseudoaneurysms (PSAs). We will also review the indications, contraindications, and complications of AML embolization.

Material and Methods: We include three representative case examples of patients treated with an array of embolic materials. Case 1: A 38 year-old female with a history of tuberous sclerosis presents following initial particle embolization for large, symptomatic bilateral AMLs. Case 2: A 95 year-old female with a history of hypertension presents with an incidentally discovered 9 cm left renal AML. Case 3: A 69 year-old male presents with left-sided abdominal pain while urinating. CT revealed a large retroperitoneal hematoma secondary to a bleeding 5 cm left renal AML.

Results: Case 1: The large left and right renal AMLs are successfully embolized with 250 um and 400 um particles, respectively. Case 2: Angiography of the left renal artery reveals the 9 cm left renal AML to be predominately supplied by a large feeding left adrenal artery. The AML is embolized with 9 cc of 5:1 alcohol to lipiodol mixture. Case 3: Angiography of the left kidney demonstrates a 1.5 cm PSA emerging from the interpolar segmental renal artery branches. Also noted is tumor blush within the midportion of the left kidney corresponding to the known left renal AML. On a subsequent angiogram, there is frank extravasation of contrast at the site of the PSA. Coil embolization of the PSA and AML is successfully performed.

Conclusions: Transarterial embolization is considered the standard of care for symptomatic renal AMLs and those measuring greater than 4 cm. Multiple embolic materials are utilized to treat renal AMLs including liquid embolics, particles, and microcoils.