Tuberous Sclerosis Care--Angiomyolipomas (AML)

What is an AML?

"AML" is the abbreviated term for angio-myolipoma.  In TS, AML's are most commonly found in the kidney.  The liver is another common location.  AML's consist of three types of tissue:  vascular/blood vessels ("angio"), muscular ("myo") and fatty ("lipoma")--hence the name angio-myo-lipoma.  One or a few AML's can be seen sporadically in people without TS.  In TS, many AML's of varying size can occur.

Is this Kidney Cancer?

Angiomyolipomas are usually benign tumors.  However, complications can develop.  AMLs can bleed.  The AML blood vessels are typically abnormal.  They contain small pouches ("aneurysms") which are weak and can rupture.  The bleeding can be massive and life threatening.  In some cases, the kidneys can be damaged or destroyed by multiple large AMLs.   Some, but not most people with TS, may eventually need dialysis or kidney transplant.

People with TS may have an increased risk for kidney cancer, but fortunately this is still not very common. 

How Do We Know It Is An AML?

A nephrologist will usually order imaging tests of the kidneys.  Options include ultrasound, CT scan, and MRI.  Most AML's appear as kidney masses with fatty tissue.  These imaging tests can detect the fat.  If fat is seen, it is most likely an AML.  If fat is not detected, the diagnosis is less certain.  If a kidney mass is present without fat, it could be a "fat poor" AML or a possibly a kidney cancer.

How Do You Treat an AML?

If an angiomyolipoma grows large, usually 4cm or greater, it needs to be treated.  Angioembolization is the usually the treatment of choice.  Small AML's need treatment also if they are causing symptoms, such as pain or bleeding.