About 80% of TSC patients and 40% of patients with S-LAM will develop renal angiomyolipomas (AMLs), benign kidney tumors containing fatty tissue, smooth muscle cells and dysplastic blood vessels.6, 7, 8 AML cells closely resemble LAM cells, as both carry inactivating mutations in either the TSC1 or the TSC2 gene.7, 9, 10 Previous studies raised the hypothesis that renal AML cells can generate pulmonary LAM by metastasizing into the lung.7, 11. This evidence concerns the gene TSC2 and lymphangioleiomyomatosis.