Isolated left brachiocephalic vein aneurysm presenting as a symptomatic mediastinal mass.

Thoracic venous aneurysms arising from the mediastinal systemic veins are very rare conditions. We report a case of a 42-year-old female who presented with dull aching pain in the left infraclavicular region, dyspnea and palpitation since 4-5 month. Chest roentgenogram revealed superior mediastinal widening secondary to a mass. Contrast enhanced CT scan revealed a homogenously enhancing superior mediastinal mass. Selective left brachiocephalic vein venography confirmed the diagnosis of an isolated large left brachiocephalic vein saccular aneurysm. The patient is being followed up without surgical treatment. Although rare a diagnosis of innominate vein aneurysm should be considered when a uniformly attenuating mediastinal mass is seen on CT so that unnecessary biopsy and surgery can be avoided.