Pulmonary lymphangioleiomyomatosis.

Lymphangioleiomyomatosis is an uncommon lung disease primarily affecting women of childbearing age. It is characterized by the progressive proliferating and infiltrating smooth musclelike cells (lymphangioleiomyomatosis cells), which lead to the cystic destruction of the lung parenchyma; obstruction of airways, blood vessels, and lymphatics; and loss of pulmonary function. Lymphangioleiomyomatosis cells coexpress smooth muscle markers (such as smooth muscle actin and desmin) and melanocytic markers (such as HMB-45, Melan-A/MART-1, and microphthalmia transcription factor). Dyspnea on exertion and recurrent pneumothorax are the most common clinical features. Somatic or genetic mutations of tumor suppressor genes tuberous sclerosis complex (TSC) 1 or TSC2 are closely related to lymphangioleiomyomatosis. The TSC1/TSC2 protein-related signaling pathways are involved in the pathogenesis and may provide novel therapeutic targets for lymphangioleiomyomatosis and diseases associated with TSC1 / TSC2 dysfunction.