Blue rubber bleb nevus syndrome and pulmonary hypertension: an unusual association.

Introduction: Blue rubber bleb nevus syndrome (BRBNS) is a rare congenital systemic angiodysplasia with multiple vascular malformations in the skin, gastrointestinal tract and, less often, in other internal organs and the brain.

Case Report: A 36-year-old man with past history of BRBNS was admitted to our hospital for progressive dyspnea and fatigue. Primary pulmonary hypertension (PPH) was diagnosed. He then developed acute abdominal pain and dyspnea, dying in a few hours due to sudden cardiac arrest. Postmortem examination demonstrated angiomatous lesions located in the skin, small bowel, heart, lungs, liver and thyroid. The lesions were slightly raised, soft and compressible and microscopically consisted of dilated vascular channels lined by a flattened endothelium. The vascular wall was formed by several layers of smooth muscle cells, intermixed with abundant aggregates of elastic lamellae and thin collagen fibers. Luminal thrombi were a frequent finding. In the small bowel, we identified the presence of an abnormally large artery directly opening into a thin-walled venous channel. The most striking finding in the lungs was the presence of thrombi of varying age in the lumen of segmental and elastic arteries, as well as muscular arteries and arterioles. Severe medial hypertrophy of muscular arteries and muscolarization of arterioles were also present. Intimal proliferative lesions and plexiform lesions were never observed.

Conclusion: The pulmonary findings are consistent with recurrent thromboembolic events from shunts in the visceral lesions. To our knowledge, this is the first report of BRBNS with visceral arterovenous (AV) fistulae complicated by thromboembolic pulmonary hypertension (PH).