[Clinical and molecular epidemiology of lymphangioleiomyomatosis and pulmonary pathology in tuberous sclerosis].

Pulmonary lymphangioleiomyomatosis is characterized by a proliferation of abnormal smooth muscle cells in peribronchial, perivascular and perilymphatic areas leading to cystic destruction of the pulmonary parenchyma. Recent clinical series of LAM have been helpful in better describing the various clinical and radiological forms of the disease, although our understanding of the pathophysiological mechanisms of LAM remains very limited. Significant progress has been noted in recent years with the discovery of probable antigenic and genetic similarities between pulmonary lymphangioleiomyomatosis, Bourneville tuberous sclerosis and renal angiomyolipoma. The proliferating cells in LAM share with normal smooth muscle cells their reactivity with desmine, vimentin and actin but certain are different by their reactivity with the monoclonal antibody HMB45, a common antigen marker of melanocyte differentiation cells, clear-cell lung carcinomas or renal angiomyolipomas. A loss heterozygosity in the region of the TSC2 gene in renal angiomyolipomas has been demonstrated in association with pulmonary lymphangioleiomyomatosis. The TSC2 gene is particularly implicated in the pathogenesis of Bourneville tuberous sclerosis.