Pediatric Renal Angiomyolipomas in Tuberous Sclerosis Complex

Tuberous sclerosis complex is a genetic disorder characterized by the growth of hamartomas in multiple organs. Up to 80% of patients with tuberous sclerosis complex will have at least 1 angiomyolipoma in their lifetime. We describe the incidence and natural history of angiomyolipoma in a pediatric tuberous sclerosis complex population and analyze tumor growth to determine optimal renal imaging intervals in an effort to improve counseling, treatment and followup.

We performed a retrospective chart review of all patients with tuberous sclerosis complex from 2004 to 2014. Patients were included if they had a clinical or genetic diagnosis of tuberous sclerosis complex and had undergone at least 1 renal imaging study.

A total of 145 patients were analyzed. Median age was 14 years (range 0 to 28). Overall incidence of angiomyolipoma was 50.3%. Median age at first angiomyolipoma detection was 11 years (range 2 to 26). Median yearly angiomyolipoma growth rate stratified by age at first detection was 0.0 mm for patients 0 to 6 years old, 0.9 mm for those 7 to 11 years old, 2.5 mm for those 12 to 16 years old and 1.8 mm for those 17 years old or older. Median yearly angiomyolipoma growth rate stratified by tumor size at first detection was 0.1 mm for tumors 0.6 to 0.9 cm, 1.8 mm for those 1.0 to 1.9 cm and 4.3 mm for those 2.0 to 2.9 cm. A total of 35 patients (24.1%) received mTOR (mammalian target of rapamycin) inhibitors. Eight patients underwent a total of 13 surgical interventions, of whom 2 had previously been treated with mTOR inhibitors. Median patient age at surgical intervention was 18.0 years and median angiomyolipoma size was 5.0 cm.

Angiomyolipoma growth in children with tuberous sclerosis complex can be rapid and unpredictable. We recommend yearly renal ultrasound in all patients with tuberous sclerosis complex, with consideration of magnetic resonance imaging in those at risk for rapid growth and future intervention (ie those older than 11 years and/or those with renal angiomyolipomas larger than 2 cm).