E4521. Renal Angiomyolipoma: Diagnosis and Management
  1. Kristy Patel; Rowan-Virtua, School of Osteopathic Medicine; University of Alabama at Birmingham
  2. Alyssa Knight; University of Alabama at Birmingham
  3. Kasey Helmlinger; University of Alabama at Birmingham
  4. Junaid Raja; University of Alabama at Birmingham
  5. Aliaksei Salei; University of Alabama at Birmingham
  6. Junjian Huang; University of Alabama at Birmingham
  7. Andrew Gunn; University of Alabama at Birmingham
Renal angiomyolipoma (AML) is the most common benign neoplasm in the kidney, comprised of adipose tissue, smooth muscle cells, and abnormal blood vessels. It accounts for 1-2% of all tumors in the kidney with an incidence of only 0.3-3% in the general population. Notably, up to 20% of AML cases are associated with tuberous sclerosis complex and are found in approximately 80% of individuals with this condition. AMLs occur sporadically with up to 40% presenting with severe hemorrhage. Interventional radiology (IR) can perform embolization for both prophylaxis and treatment of bleeding, and percutaneous ablation can be employed for hypovascular AMLs.

Educational Goals / Teaching Points
Diagnose renal angiomyolipoma (AML) through a case-based review of ultrasound (US), CT, and MRI findings. Review available management strategies for AML, including observation, medications, transarterial embolization (TAE), percutaneous ablation, and surgery. Discuss patient selection and technical considerations for TAE in a case-based format. Understand patient selection and technical considerations for percutaneous ablations of AMLs in a case-based format.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Sporadic AMLs are most commonly diagnosed as an incidental finding on either US, CT, or MRI with macroscopic fat being considered diagnostic even though ‘fat-poor’ AMLs can be encountered. AMLs can have abnormal blood vessels that can become dilated and rupture, especially when the aneurysms are > 5 mm. Small, asymptomatic AMLs can generally be observed. Symptomatic and/or ruptured AMLs should be treated with urgent TAE. Due to the risk of rupture resulting in life-threatening bleeding, TAE is generally recommended for when the mass is > 4 cm, even if the patient is asymptomatic. TAE for AMLs results in high rates of clinical success, with an overall low rate of major complications. The advent of smaller microcatheters and balloon-occlusion microcatheters allows for subselection of renal vessels, leading to preserved renal function. A variety of embolic agents, including absolute ethanol, particles, and glue can be successfully used. A subset of AMLs are hypovascular on CT or catheter-based angiography even though these hypovascular masses can still rupture. For these patients, percutaneous ablation can be employed.

Interventional radiologists play an important role for patients with renal AMLs as part of a multidisciplinary care team.