Angiomyolipoma (AML): Causes, Symptoms, and Treatment of Kidney Angiomyolipoma

Receiving a diagnosis of “angiomyolipoma (AML) of the kidney” following an ultrasound or CT scan can be a cause for concern for many patients. However, angiomyolipoma is one of the most common causes of benign tumors in the kidney and does not always indicate cancer. Nevertheless, because it can carry a risk of bleeding when it grows to a large size, regular follow-up and proper evaluation are of great importance.

AsProf. Dr. Volkan İzol, when evaluating patients diagnosed withangiomyolipoma, I first assess the size of the mass, its growth rate, and the risk of bleeding. This allows us to avoid unnecessary surgery while ensuring that patients who require intervention receive timely treatment.

What Is an Angiomyolipoma (AML)?

Angiomyolipoma (AML) is one of the most common benign tumors of the kidney, consisting of blood vessels (angio), smooth muscle (myo), and fatty tissue (lipoma).

Although it is most commonly seen in a single kidney and as a single lesion, in some patients it can develop in both kidneys at the same time.

What Causes an Angiomyolipoma?

The exact cause of most cases of AML is unknown.

However, it may be associated with certain conditions:

  • Spontaneous (sporadic) cases
  • A genetic disorder known as Tuberous Sclerosis Complex (TSC)
  • Rare cases of lymphangioleiomyomatosis (LAM)

Sporadic AMLs are typically unilateral and smaller in size. In patients with tuberous sclerosis, however, larger and more numerous lesions may be observed.

What Are the Symptoms?

Smallangiomyolipomasoften cause no symptoms and are discovered incidentally during an ultrasound or CT scan performed for another reason.

As they grow, the following symptoms may appear:

  • Side or flank pain
  • Blood in the urine (hematuria)
  • A feeling of fullness in the abdomen
  • Nausea
  • Rarely, low blood pressure and sudden, severe pain (when bleeding occurs)

Particular caution is required due to the risk of bleeding, especially in cases of large AMLs.

Is an Angiomyolipoma Cancer?

No.

An angiomyolipoma is a benign kidney tumor and is not the same condition as kidney cancer.

However, in some rare "fat-poor" types of AML, it can be difficult to distinguish them from kidney cancer using imaging. For this reason, advanced imaging techniques and an experienced evaluation are crucial.

How Is the Diagnosis Made?

The most commonly used diagnostic methods are as follows:

  • Ultrasound of the Urinary System
  • Contrast-enhanced computed tomography (CT)
  • Magnetic Resonance Imaging (MRI)

The fat content of AML often allows for a diagnosis to be made using imaging techniques.

Is Treatment Necessary?

Not everyangiomyolipomarequires surgery.

The decision regarding treatment is made based on the following criteria:

  • Tumor size
  • Growth rate
  • The patient is experiencing pain or bleeding
  • High risk of bleeding
  • Pregnancy Plan
  • The patient's overall health

Small, asymptomatic AMLs are generally monitored at regular intervals.

What Are the Treatment Options?

Treatment is tailored to each individual.

Methods that can be used in suitable patients:

  • Monitoring through regular check-ups
  • Selective angiembolization (occlusion of a blood vessel to prevent bleeding)
  • Kidney-sparing surgery (partial nephrectomy)
  • Drug therapy in selected patients (particularly mTOR inhibitors in AMLs associated with tuberous sclerosis)

The goal is to preserve as much healthy kidney tissue as possible.

When Should You Seek Emergency Care?

If you experience any of the following symptoms, you should seek medical attention immediately:

  • Sudden, severe pain in the side
  • The presence of a large amount of blood in the urine
  • Don't feel like you're going to faint
  • Cold sweats
  • Low blood pressure

These findings may indicate bleeding associated with AML and may require urgent intervention.

Conclusion

Angiomyolipoma is one of the most common benign tumors of the kidney and can be successfully monitored or treated in most patients. AsProf. Dr. Volkan İzol, I explain to my patients that not every kidney mass is cancerous, but that an accurate diagnosis and regular follow-up are of great importance. Thanks to advanced imaging techniques and kidney-sparing treatment options available today, successful outcomes are achieved in many patients while preserving kidney function.