Angiomyolipomas
Angiomyolipomas (AMLs) are benign tumours, usually, but not exclusively found in the kidney, which consist of vascular, smooth muscle and fat tissue. They are benign in that they are non-cancerous, but in rare cases, they can be sufficiently numerous as to cause chronic kidney disease, and they can bleed to a sufficient degree as to be a surgical emergency. In the majority of cases, people with an angiomyolipoma are asymptomatic from it.
Angiomyolipomas are found in something like 0.5% of the population and are usually diagnosed as an incidental finding on an unrelated ultrasound scan. There is a strong association with tuberous sclerosis, and other rare diseases, but the vast majority of cases are sporadic.
The likelihood of a single angiomyolipoma causing any adverse clinical events is related to its size. Lesions below 2cm in diameter are very unlikely to cause problems and there is debate as to whether they require monitoring by ultrasound or can be ignored completely. Our guidance would be as follows:
AML<2cm in diameter
Repeat ultrasound at 2-4 years and if stable over a period of years, repeat scan only for a change in clinical condition. If in doubt, request urology advice.
AML 2-4cm in diameter
Screen with yearly ultrasound. Discuss with urology if there is any increase in size.
AML>4cm in diameter
Refer to urology.
Multiple and / or bilateral AMLs
Consider diagnosis of tuberous sclerosis.
Everolimus is a medicine that has been approved for the management of AMLs in association with tuberous sclerosis but requires specialist initiation.
Acknowledgements
This page was written in June 2024 by Paddy Gibson.