but for those that are not, it is recommended to perform an ultrasonography after 6 months, and then annually if stable. Prognosis Small Angiomyolipomas and those without dilated blood vessels (aneurysms) cause few problems, but Angiomyolipomas have been known to grow as rapidly as 4 cm in one year. Angiomyolipomas larger than 5 cm and those containing an aneurysm pose a significant risk of rupture, which is a medical emergency, as it is potentially life-threatening. One population study found the cumulative risk of hemorrhage to be 10% in males and 20% in females. A second problem occurs when the renal Angiomyolipomas take over so much kidney that the function is impaired, leading to chronic kidney disease. This may be severe enough to require dialysis. A population survey of patients with TSC and normal intelligence found 1% were on dialysis. Epidemiology Angiomyolipomas are the most common benign tumor of the kidney, and are found either in patients with Tuberous Sclerosis or sporadically. About 80–90% of cases are sporadic, and these are most commonly found in middle-aged women. In patients with TSC, a longitudinal study found 80% will have some form of renal lesion by around 10 years of age. Of these, 75% are Angiomyolipomas and 17% are cysts. The Angiomyolipomas increased in size in around 60% of these children. An autopsy study and TSC clinic survey found a prevalence of 67 and 85%, respectively, for patients with TSC. Both genders are affected equally. References External links Benign neoplasms Urological neoplasia Benign renal neoplasms