Ruptured venous aneurysm of the persistent left superior vena cava.

A 24-year-old female with venous aneurysm of the persistent left superior vena cava and the left subclavicular vein has been reported. Spontaneous closed rupture of the venous aneurysm, secondary to thrombosed obstruction, occurred into the posterior mediastinum and the extrapleural thoracic wall. The symptom was aggravated rapidly because of absent communicating vein between the persistent left superior and the right superior venae cavae. Surgical intervention was not considered for the reason of difficulty in approach. Fortunately an open rupture of the venous aneurysm into the thoracic cavity was not seen. A conservative treatment for 4 months resulted in a successful outcome with absorption of a large hematoma and building of collateral circulation.