Kidney Disease · Renal Angiomyolipoma

Protect your kidney from a bleeding angiomyolipoma

An angiomyolipoma (AML) is a benign kidney tumor that can bleed. Embolization shrinks the tumor and lowers the risk of bleeding by blocking its blood supply through a pinhole in an artery. There is no incision, and the healthy part of the kidney is preserved.

Call to book: 737-241-2184 How embolization works
Understanding the condition

What is an angiomyolipoma?

An angiomyolipoma is a non-cancerous kidney tumor made of blood vessels, smooth muscle and fat. It is often found by chance on a scan done for another reason. Most occur on their own, but some are linked to tuberous sclerosis complex (TSC), a genetic condition in which people often have several AMLs in both kidneys.

The main concern is bleeding. The blood vessels inside an AML are abnormal and can form small aneurysms. Larger tumors and larger aneurysms are more likely to bleed, sometimes suddenly and heavily, into the space around the kidney.3,4

Embolization blocks the abnormal vessels that feed the tumor. Without its blood supply, the AML shrinks over the following months and is much less likely to bleed, while the rest of the kidney keeps working.

Diagram of a kidney with an angiomyolipoma fed by an artery branch, and the same kidney after embolization with a smaller tumor Angiomyolipoma Abnormal vessels can bleed AML artery After embolization Tumor shrinks, kidney preserved tumor's feeding vessels blocked
Simplified illustration. Embolization blocks the vessels feeding the angiomyolipoma, which then shrinks, while the healthy kidney keeps its blood supply.
Is embolization right for me?

Who is a good candidate?

Many small AMLs never cause problems. Treatment is usually considered when the risk of bleeding is higher or the tumor causes symptoms. Embolization is often a good fit if you have:3,4

  • An AML of about 4 cm or larger, or one that is growing, especially if it has many blood vessels.
  • An aneurysm of 5 mm or more inside the tumor on CT or MRI.
  • Symptoms such as flank pain or blood in the urine.
  • Sudden bleeding from an AML. Embolization is the first-line emergency treatment when it is available.3
  • TSC-related AMLs that have not responded to medication or need faster control.3
  • A wish to avoid surgery and protect as much kidney function as possible.

Small AMLs without symptoms can often be watched safely with regular scans. In a large review, only about 2% of patients under surveillance had a bleed. There is no single size at which everyone needs treatment, so the decision also depends on your age, the tumor's growth and your preferences.2

Evaluation

How we decide whether embolization is right for you

We work closely with Urology Austin to review your scans, your symptoms and your kidney health before recommending treatment.

1

Consultation

We review your history, symptoms and any family history of TSC, and explain every option, including watching the tumor.

2

CT or MRI

Cross-sectional imaging confirms the diagnosis by showing fat inside the tumor, and measures its size, blood vessels and any aneurysms.

3

Kidney function tests

Blood tests check your kidney function, so we can plan a treatment that protects it.

Treatment

How embolization compares with other options

The right approach depends on the size and behavior of your AML, whether you have TSC, and your overall health.

OptionHow it worksThings to know
Active surveillance Regular CT, MRI or ultrasound scans to watch the tumor Suitable for most small AMLs without symptoms; bleeding is uncommon2
Medication (mTOR inhibitors) Daily tablets such as everolimus shrink AMLs First-line for many people with TSC; tumors can regrow if the medication is stopped3
Partial nephrectomy The tumor is surgically removed, keeping the rest of the kidney Lowest chance of needing further treatment, but it is an operation with a longer recovery2
Embolization The tumor's blood supply is blocked through a pinhole in an artery No incision, kidney preserved, first-line for active bleeding; some patients need a repeat treatment1,3
The procedure

What happens during AML embolization

Planned embolization typically takes one to two hours. You are awake but relaxed throughout.

  1. Preparation

    You receive light sedation and local anesthetic at the access site, and often medication to reduce discomfort and inflammation afterward.3

  2. A pinhole in the wrist or groin

    A thin tube (catheter) is placed into an artery in your wrist or upper thigh through a tiny puncture. No incision is made.

  3. Mapping the arteries

    Using X-ray guidance and contrast dye, a microcatheter is steered into the kidney artery and then into the small branches that feed the tumor.

  4. Embolization

    Tiny particles, a liquid agent and/or small coils are used to close off the tumor's vessels and any aneurysms, while protecting the blood supply to the healthy kidney.4

  5. Recovery

    The catheter is removed and a small dressing applied. You rest for 30 to 60 minutes and go home the same day with medication and clear instructions.

What the research shows

Results

Embolization has been used for AMLs for decades. A systematic review of 31 studies and more than 500 procedures summarizes the results.1

66%

Average reduction in tumor volume after embolization in a series of 50 AMLs. Seven in ten shrank by at least half.4

0

Deaths related to the procedure across the 524 embolizations in the systematic review. Further complications occurred in about 7%.1

1 in 5

Patients who needed a repeat embolization or surgery over an average of about 3 years, most often because new vessels had grown into the tumor.1

Tumors shrink gradually over several months, and we follow you with scans to check the result. AMLs in people with TSC are more likely to regrow, so long-term follow-up matters.4 Individual results vary, and no treatment can guarantee success.

Safety

Risks and side effects

Serious complications are uncommon. We discuss all risks with you in detail beforehand:

  • Post-embolization symptoms in about a third of patients: flank pain, fever, nausea and tiredness for a few days. These are expected and managed with medication.1
  • Loss of a small amount of normal kidney tissue near the tumor, which rarely affects overall kidney function
  • Rarely, an infection or abscess in the treated tumor
  • Bruising or tenderness at the wrist or groin puncture site
  • Reaction to contrast dye or sedation
  • Regrowth of the tumor over time, which may need repeat embolization1,2
Questions

Frequently asked questions

Is an angiomyolipoma cancer?

No. An AML is a benign (non-cancerous) tumor. It is treated because of the risk of bleeding or symptoms, not because it spreads.

Will I lose my kidney?

No. The goal of embolization is to treat the tumor while preserving the healthy part of the kidney.

Is the procedure painful?

The procedure itself is done under sedation and local anesthesia. Flank pain for a few days afterward is common, and we give you medication to manage it.

How soon can I get back to normal activities?

Most people return to light activities within a few days to a week. Your physician will give you specific instructions about exercise and lifting.

Will I need more scans afterward?

Yes. Follow-up CT or MRI scans show how much the tumor has shrunk and whether any new vessels have formed that need treatment.

Is it covered by insurance?

Coverage varies by policy. We will navigate out-of-pocket costs with you. Call us at 737-241-2184 with questions.

Find out whether embolization is right for you

If you have been told you have a renal angiomyolipoma, an evaluation can show whether it should be watched or treated, and whether embolization is a good option.

Call 737-241-2184 to schedule

References

  1. Murray TE, Doyle F, Lee M. Transarterial embolization of angiomyolipoma: a systematic review. J Urol. 2015. PMID 25916674
  2. Fernández-Pello S, Hora M, Kuusk T, et al. Management of sporadic renal angiomyolipomas: a systematic review of available evidence to guide recommendations from the European Association of Urology Renal Cell Carcinoma Guidelines Panel. Eur Urol Oncol. Author manuscript
  3. Mekahli D, Müller RU, Marlais M, et al. Clinical practice recommendations for kidney involvement in tuberous sclerosis complex: a consensus statement by the ERKNet Working Group for Autosomal Dominant Structural Kidney Disorders and the ERA Genes & Kidney Working Group. Nat Rev Nephrol. 2024;20:402–420. doi:10.1038/s41581-024-00818-0
  4. Hongyo H, Higashihara H, Osuga K, et al. Efficacy of prophylactic selective arterial embolization for renal angiomyolipomas: identifying predictors of 50% volume reduction. CVIR Endovasc. 2020;3:84. doi:10.1186/s42155-020-00179-2

This page provides general information and does not replace a personal medical consultation. Study results describe groups of patients and cannot predict the outcome for an individual. Urology Austin and IR Centers · 8701 N. Mopac, Suite 100, Austin, Texas 78759 · 737-241-2184