Tuberous sclerosis complex (TSC) is an autosomal dominant disorder caused by mutations in tuberous sclerosis complex 1 (TSC1) or TSC2 tumor suppressor genes. TSC is characterized by tumors in a wide range of tissues, seizures, mental retardation, autism, and organ failure. Lymphangioleiomyomatosis (LAM), the major pulmonary manifestation in women with TSC, is a progressive lung disease characterized by infiltration of atypical smooth muscle like cells (TSC-/- LAM cells) and formation of parenchymal cysts. Sporadic LAM can develop in women who do not meet the criteria for the diagnosis of TSC, owing to somatic mutations in the TSC2 gene.