Pulmonary arterial involvement leading to alveolar hemorrhage in lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare disorder of unknown cause that affects women of reproductive age. The disorder is characterized by the proliferation of atypical smooth muscle cells (LAM cells) around airways, blood vessels, and lymphatics with cystic destruction of the lung. LAM may occur sporadically or may be associated with tuberous sclerosis complex (TSC). Clinically, patients may develop progressive dyspnea, cough, wheezing, spontaneous pneumothorax, chylothorax, and hemoptysis. The diagnosis is confirmed by the identification of diffuse thin-walled lung cysts via thoracic high resolution computed tomography (HRCT) that are associated with a positive tissue biopsy or by the presence of chylothorax, angiomyolipoma, or TSC. Acute respiratory failure that is secondary to diffuse alveolar hemorrhage is an extremely rare manifestation in LAM patients, with only two previous cases described. The mechanism responsible for the comorbid presentation of acute respiratory failure and diffuse alveolar hemorrhage, however, is unknown. Nonetheless, it is speculated to be secondary to the obstruction of pulmonary venules by LAM cell proliferation, thereby promoting pulmonary venous hypertension. In the present work, we describe a patient with a diffuse alveolar hemorrhage that led to acute respiratory failure and death. A diagnosis of LAM and pulmonary arterial disruption caused by LAM cells was confirmed during the autopsy.