Fig. 1. Left renal arteriogram revealing an ill-defined hypovascular mass (arrows) in the periphery of the left lower pole. A patent segmental feeding artery can be seen coursing toward the mass.

This 62-year-old Caucasian female was diagnosed with a solitary left lower renal angiomyolipoma on an ultrasound study 5 years ago. The lesion was periodically imaged until a recent MRI revealed an increase in the size of the lesion to greater than 4 cm (4.6x4.8cm). The patient was referred to Interventional Radiology for embolization of the AML given the increased risk of bleeding with a lesion greater than 3 cm. Both embolization and surgical treatments were discussed with the patient, who elected to undergo the embolization procedure. The patient had always been asymptomatic with no flank pain or hematuria.

The initial attempt at embolization was unsuccessful due to spontaneous spasm/thrombosis of the segmental vessel feeding the tumor. No embolics were administered and the patient was scheduled to return for a repeat attempt in 2 weeks.

A repeat left renal arteriogram performed during the second session showed patency of the previously thrombosed/constricted interpolar segmental branch leading to the AML (Figure 1). After selection of this vessel with a microcatheter, the lesion was found to harbor a venous lake (Figure 2). There was also rapid filling of the renal venous sinus following injection of the single, predominant feeding segmental artery (Figure 3).

Embolization was then performed with 350 to 500 micron size PVA particles after the infusion of 1cc of alcohol mixed with 0.2 cc of Ethiodol into the vessel. Interval thrombosis/spasm of the feeding vessel again occurred during embolization despite prior treatment with 100 mcg of nitroglycerin. An additional 100 mcg of nitroglycerin and 3000 units of heparin were given. The thrombosed/spasmed vessel was then crossed with a wire, allowing for continued embolization with complete stasis in the feeding artery and staining of the renal mass. The patient tolerated the procedure well and was discharged from the IR service the following day. Follow-up imaging is scheduled at 3 months.

1. Are you performing prophylactic embolization for large AMLs? If so, what is your size threshold?

2. Given the appearance of this renal mass with an associated venous lake and rapid filling of the venous sinus, could this lesion be something other than an angiomyolipoma?

3. How else could this lesion have been managed given the complications with thrombosis/spasm of the feeding vessel?

4. Would you have coiled the feeding vessel?

References:

1. Soulen MC, Faykus MH Jr., Shlansky-Goldberg RD, Wein AJ, Cope C. Elective embolization for prevention of hemorrhage from renal angiomyolipomas. J Vasc Interv Radiol 1994;5:587-91.

2. Hamlin JA, Smith DC, Taylor FC, McKinney JN, Ruckle HC, Hadley HR. Renal angiomyolipomas: long-term follow-up of embolization for acute hemorrhage. Can Assoc Radiol J 1997;48:191-8.

3. Lee W, Kim TS, Chung JW, Han JK, Kim SH, Park JH. Renal angiomyolipoma: embolotherapy with a mixture of alcohol and iodized oil. J Vasc Interv Radiol 1998;9:225-61.

Case 1097_03 -- Embolization of Angiomyolipomas
Case 0698_03 -- Embolotherapy for Angiomyolipoma