[Lymphangioleiomyomatosis: Update on Pathophysiology, Diagnosis, and Treatment]

Interstitial lung diseases (ILDs) include a group of rare and complex pathologies, among which lymphangioleiomyomatosis (LAM) stands out. LAM is considered a neoplastic disease characterized by abnormal proliferation of smooth muscle cells in the lung, forming cysts and causing severe respiratory alterations. LAM primarily affects women of childbearing age and can present in two forms: sporadic (S-LAM) and associated with tuberous sclerosis complex (TSC-LAM). Although its etiopathogenesis is not fully understood, genetic and hormonal pathophysiological mechanisms have been studied. Genetic alterations in the TSC1 and TSC2 genes lead to uncontrolled activation of the mTOR pathway, resulting in the transformation of smooth muscle cells into abnormal cells known as LAM cells. The activation of hormonal receptors present in LAM cells increases cell proliferation and migration. The perialveolar proliferation of these cells may explain alveolar rupture and cyst formation. There is also matrix remodeling and production of lymphangiogenic growth factors, such as vascular endothelial growth factor-D (VEGF-D), which contributes to the formation of lymphatic vessels in LAM lesions and cystic remodeling of the lung. The most common symptoms are exertional dyspnea and recurrent pneumothorax, along with other extrapulmonary manifestations such as renal angiomyolipomas. Diagnosis is based on characteristic tomographic findings and elevated plasma levels of VEGF-D. Treatment focuses on improving quality of life and halting disease progression. Sirolimus, an mTOR inhibitor, is the first-line therapy and has shown to stabilize lung function and reduce symptoms. In advanced cases, lung transplantation is a viable option. Hormone therapy and some surgical procedures are currently not recommended due to inconsistent results.