Lymphangioleiomyomatosis: a rare disease

Pulmonary lymphangioleiomyomatosis (LAM) is a rare interstitial disease of uncertain etiology that occurs almost exclusively in women, most often in childbearing age. This disease is sometimes associated with tuberous sclerosis complex, TSC-LAM, or, more rarely, micronodular pneumocyte hyperplasia, a circumscribed proliferation of type 2 pneumocytes. LAM is characterized by proliferation in the bronchioli, pulmonary veins and lymphatic vessels of cysts lined by atypical smooth muscle cells that show reactivity to the HMB-45 monoclonal antibody. Progressive occlusion of these structures most often leads to serious clinical manifestations including worsening dyspnea, often accompanied by cough, chest pain, hemoptysis, pneumothorax or chylothorax. The main treatment option is suppression of sexual hormones by various manipulation strategies. However, optimal treatment for LAM patients is still debated, although an effect of hormonal manipulation has been recently reported: these clinical findings also seem to be supported by in vitro data showing that LAM pathogenesis is at least in part directly related to an estrogen-driven mechanism.