Pulmonary arterial fibromuscular dysplasia: a rare cause of fulminant lung hemorrhage.

Arterial fibromuscular dysplasia (FMD) represents a collection of noninflammatory and nonatherosclerotic vascular diseases with a poorly understood etiology. Classically occurring in renal and cerebral arteries, this entity has also been reported in coronary, carotid, and other medium and small arteries. One case occurring in the pulmonary vasculature has been reported. Fatal hemothorax and lung hemorrhage have multiple causes, including other vascular malformations and connective tissue disorders; however, cases of pulmonary FMD are exceedingly rare. We report what appears to be the second such association, occurring in a 69-year-old man. The patient presented with a 3-week history of increasing dyspnea, fatigue, and productive cough; 3 days of increasing back and chest pain; and syncope. Chest radiograph showed a "white-out" of the left lung. The patient died shortly after admission from a fulminant respiratory disease of undetermined etiology. At autopsy he was found to have a massive left hemothorax resulting from an unsuspected pulmonary arterial fibromuscular dysplasia.