Inherited mutations of the TSC1 or TSC2 gene cause tuberous sclerosis while acquired (somatic) mutations of either gene are associated with sporadic lymphangioleiomyomatosis (LAM). Renal angiomyolipomas are a feature of both disorders. TSC1 and TSC2 regulate signalling through the mammalian target of rapamycin (mTOR) pathway. Inhibition of mTOR may result in a decrease in size of TSC 1/2 assciated lesions. We are treating patients with tuberous sclerosis or sporadic LAM with the mTOR inhibitor rapamycin in a non-randomised, open label pilot study of safety and efficacy. Change in size of renal angiomyolipomas is the primary end point