Renal angiomyolipoma (AML)

Renal angiomyolipoma (AML) refers to a bengin (non-cancer) mass lump in the kidney that is composed primarily of fat tissue, muscle, and blood vessels. It is the most common type of benign (non-cancer) kidney tumour and may be detected incidentally (without symptoms) on imaging scans such as CT or MRI. AMLs may also present with bleeding, abdominal pain, and haematuria (blood in urine). Most AMLs occur without any particular cause (sporadic), however it may occur as part of the Tuberous Sclerosis Complex (TSC).

The majority of renal AMLs do not require treatment, as they are small and unlikely to cause any symptoms or issues in the future. These AMLs are generally managed with observation over time, including repeat imaging scans as appropriate. An AML may require treatment with embolisation if:

• It is <4 cm in size
• It contains an aneurysmal (abnormally dilated) blood vessel
• It has caused bleeding

As AMLs are benign (non-cancer), the reason to treat is to minimise the risk of future growth and haemorrhage (bleeding).

Embolisation by an Interventional Radiologist (IR) is a safe and effective treatment for AML, and is typically the first-line treatment recommended when an AML has grown larger than 4 cm, has an aneurysmal blood vessel, or has caused bleeding. The procedure is performed by passing a catheter into the arteries that supply the AML, and occluding (blocking) them with embolic material such as particles, alcohol, glue or coils.

Effectiveness

• The procedure is successful in closing off the blood supply to the AML in over 90% of cases, with a small number requiring a repeat procedure
• Up to 30% of patients may require further treatment in the future due to regrowth of the AML, typically several years later

1. A specialist interventional radiologist will first consult and examine you to determine your suitability for the embolisation procedure. If the AML does not yet require treatment, the interventional radiologist with you about a follow-up monitoring plan including repeat imaging.
2. Most renal AML embolisation procedures are performed under sedation and local anaesthetic via a small catheter tube inserted into the femoral artery in your groin. In some cases access into an upper limb (arm) artery may be required.
3. The procedure typically takes between 1 and 2 hours
4. There may be a closure device or "stitch" used to seal the site where the catheter was inserted into the artery
5. You will be required to lie down and rest in bed for up to 4 hours post-operatively, which is to minimise bruising in the groin.
6. The procedure may be performed as a day-case or with an overnight hospital stay depending on complexity
7. You may experience a "post-embolisation" syndrome after the procedure, which can include a dull abdominal pain and nausea, which will be treated with medications
8. After returning home, most patients are able to return to normal activities including work within 3-5 days
9. Follow up consultation and imaging will be arranged to ensure that the AML is completely treated and does not regrow or recur

The overall risk of major complications is  very low (<1%), but possible complications include:

• Groin bruising or haematoma (bleeding lump)
• Damage to an artery resulting in decreased blood flow to the kidney
• Decreased kidney function

Interventional Radiologists (IRs) are specialty trained in the treatment of renal AMLs, including the pre-procedural assessment, operation and post-procedural care. Interventional Radiologists (IRs) are extensively experienced in embolisation procedures as they regularly perform angiography and embolisation all throughout the body, including the kidneys, liver, spleen and pelvis.

If you would like to consult with an Interventional Radiologist about varicocele embolisation, please send a referral for consultation, including the following

• Ultrasound, CT and other imaging results
• Records of consultations with other doctors and specialists

Public eligible patients can undergo the treatment with no out-of-pocket expense in the public system.