Endovascular repair of an internal mammary artery aneurysm in a patient with SMAD-3 mutation.

Aneurysms of the internal mammary artery are rare. We describe a case of a 49-year-old woman with a SMAD3 mutation who presented with left internal mammary artery aneurysm that was thought to have ruptured, causing a large spontaneous left mediastinal hematoma. The aneurysm was treated successfully months after initial presentation with coil embolization. SMAD3 mutations are linked to familial thoracic aortic aneurysms and dissections, peripheral aneurysms, and early-onset osteoarthritis, with an estimated incidence of 2% in families with familial thoracic aortic aneurysms and dissections. To our knowledge, this is the first case in the literature to link a SMAD3 mutation with internal mammary artery aneurysm.