Brachiocephalic venous aneurysm with unusual clinical observations.

Thoracic venous aneurysm is an extremely rare condition. This report describes the case of a 70-year-old woman with a left brachiocephalic venous aneurysm that caused recurrent nerve paralysis. Contrast-enhanced computed tomography and venography revealed a venous aneurysm, 4 cm in size, located adjacent to the venous angle. Anticoagulation therapy was started, and 1-1/2 months later, the aneurysm greatly decreased in size and showed marked calcification along its periphery. Venous aneurysms that shrink after anticoagulation therapy are exceptionally rare. The clinical features of this condition have been briefly reviewed.