Congenital arteriovenous fistulas of the bilateral internal mammary vessels.

Internal mammary artery-to-venous fistulas represent a rare cause of a continuous precordial murmur that may be confused clinically with a patent ductus arteriosus. The acquired variety may be secondary to inflammatory, neoplasic, or traumatic events. A congenital fistula may occur as an isolated event, as in the present case, and the question of advisability of endovascular treatment for this patient remains unanswered.