Pulmonary capillary hemangiomatosis arising in hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is an autosomal dominant inherited disease characterized by epistaxis, telangiectases, and visceral arteriovenous malformations that can lead to hemorrhage and other complications. We report the case of a 56-year-old female patient with HHT and pulmonary hypertension who died with intractable pulmonary and gastrointestinal bleeding. Autopsy revealed vascular malformations in the lungs, gastrointestinal tract, liver, spleen, and brain. Capillary proliferations in the pulmonary alveolar walls, characteristic of pulmonary capillary hemangiomatosis, were identified, as was evidence of pulmonary hypertensive arteriopathy. To our knowledge, this is the first report of pulmonary capillary hemangiomatosis arising in HHT. The histopathologic findings of HHT and pulmonary capillary hemangiomatosis are reviewed, and a possible role for diminished capillary expression of endothelial nitric oxide synthase is discussed.