Aneurysm of the left brachiocephalic vein: an unusual cause of mediastinal widening.

A case of left brachiocephalic venous aneurysm is presented. Thoracic venous aneurysms are rare with only 27 previous cases in the medical literature, the majority involving the superior vena cava. There are only two previous reports of isolated brachiocephalic venous aneurysm. Venous aneurysms are usually first detected as mediastinal widening on a chest radiograph and can be further defined using CT, MRI or angiography. The aetiology is uncertain. Management is usually conservative, but surgical correction has been performed.