Selective transcatheter arterial embolization (TAE) of renal angiomyolipomas (AML) is a minimally invasive treatment of renal angiomyolipomas. It is appealing because it can save a significant part of the normal renal parenchyma despite tumor embolization with a superselective approach and subsequent few post-operative complications ¹.

Indications

• ruptured renal angiomyolipoma with hemorrhage

• symptomatic cases with flank pain/mass effect

• renal AML > 4 cm which may have microaneurysms as an early warning sign of increased risk of rupture

• prevention of major bleeding during pregnancy

Contraindications

• acute infection: to prevent abscess in the targeted area

• impaired global renal function (eGFR<35)

• allergic reactions to contrast media

• acute hyperthyroidism

• single kidney

Procedure

Technique

• trans-femoral access

• selective cannulation of the main renal artery

• superselective angiogram from the renal artery branch supplying the tumor

• preparing of ethanol-lipiodol mixture in 1:1 or 2:1 depending on the position of the microcatheter, vascularity, and flow (or we can use PVA, Glue, or Coils)

• start with very small volumes of the mixture (2 mL) and then extreme care and patience during the injection

• avoid reflux and nontarget embolization of mixture into normal branches

• the endpoint of embolization can arrive very abruptly

• final main renal artery angiogram

• prophylactic antibiotics ^2,5

Complications

• post embolization syndrome (PES)

  • fever (above 38.0°C), nausea, and abdominal pain

  • minimal swelling and discomfort around the catheter site

• renal abscess

• thrombosis of the renal artery

• complete loss of renal function (rarely)

• TAE may not lead to a full response

Outcome

Transcatheter arterial embolization is considered an alternative treatment choice for renal AMLs and the literature indicates that the TAE technique has significantly reduced median tumor size, with a low incidence of severe complications and no notable loss of renal function during long-term follow-up. In particular it may be considered in patient cases who are not candidates for abdominal surgery ^1-5.

Advantages

• the procedure can be carried out in an outpatient setting using local anesthesia

• non-invasive and more nephron-sparing option than surgery

• shrinkage of the mass over time

• relieve symptoms caused by tumor pressure affecting nearby tissues

• reducing the risk of internal bleeding

• an alternative treatment option for patients who are not suitable for general anesthesia, have a history of previous abdominal surgery or are at high risk of surgical complications due to other comorbidities ^1,2

Disadvantages

• no histological information is obtained, and renal cancer could potentially be missed ^1,2