Abstract
Introduction
Angiomyolipoma (AML), a form of benign renal neoplasm, generally occurs either spontaneously or due to tuberous sclerosis. Although AML is often asymptomatic and found incidentally, there are cases where spontaneous hemorrhage occurs and causes a wide variety of symptoms, sometimes progressing to shock. Angioembolization is a potentially life-saving treatment in such cases and is generally successful as a treatment. Here, we describe a patient who underwent two AML embolization procedures and was later found to have a portion of the mass in her renal collecting system.
Case Info
A 46-year-old female with no pertinent past medical history presented to the emergency department with fever and worsening left lower quadrant (LLQ) abdominal pain. Physical exam showed LLQ tenderness and guarding, 39.2 °C fever, and mild tachycardia. A CT Abdomen/Pelvis with IV Contrast was ordered, showing trace pelvic free fluid, left retroperitoneal/pelvic varicosities, and a 10.9 by 8.2 cm heterogeneously enhancing left renal mass containing fat compatible with AML. Urology consult suggested high bleeding risk given the size. The patient was admitted and treated with antibiotics. After discharge, the decision was made to pursue embolization as definitive treatment. Approximately 15 cc of a 7:3 EtOH to lipiodol mixture was injected proximal to tortuous arterial vasculature supplying the AML. Post-procedure CT for new symptoms showed a large retroperitoneal hematoma surrounding the left lower pole AML, which required transfusion. CTA further demonstrated persistent arterial phase blood flow in the superior aspect of the mass. Lateral and medial left lower pole renal artery branches were successfully embolized using n-BCA glue. The remainder of the patient’s post-operative course was largely unremarkable. Approximately 8 months later, the patient presented to the ED with a recurrence of her left flank pain, with tenderness noted on physical exam. CT Abdomen/Pelvis with IV Contrast showed a small fat density within the left ureter and mild hydronephrosis, believed to be obstruction secondary to fat from the inferior pole AML sloughing off into the collecting system. The patient excreted the fat before further follow-up, noting an “oily” appearance to her urine.
Disc Clinical
AML embolization is a highly effective procedure with a low major complication rate, though minor complications frequently occur. The most common minor complication is post-embolization syndrome. While definitions of this syndrome vary, hallmarks include fever, pain, nausea, and vomiting following the procedure. However, AML sloughing into the renal collecting system is incredibly rare, with seemingly only three cases of lipiduria following the procedure being published. These cases agree that tissue disruption during the embolization procedure is potentially contributory, and all of the cases involved an AML of 10 cm or greater. This case appears to be consistent with that assessment, though current evidence is far from conclusive.
Conclusion
Although minor complications are common, lipiduria is not typically seen following AML embolization. This may be due to underreporting by patients, especially given that the fat can be passed with urination. However, more cases are needed to truly gain an understanding of this rare complication.