Surgical resection of a thymoma developed in a case with isolated persistent left superior vena cava

Persistent left superior vena cava (PLSVC) is one of the most common vascular abnormalities in the chest. In approximately 10 % of cases, the right superior vena cava is missing, which is called isolated persistent left superior vena cava (IPLSVC).

The case is an 85 years-old female. An anterior mediastinal tumor was accidentally revealed when the patient was admitted after a traffic accident. As the tumor became larger within four months, a thymectomy was planned. The anterior mediastinal tumor was in front of the ascending aorta, which was close to the confluence of the left and right brachiocephalic veins in normal anatomy. However, in this case, the right superior vena cava was missing, and the right brachiocephalic vein flowed into the left superior vena cava by the chest computed tomography. Preoperative examinations found no accompanying cardiac abnormality. Robot-assisted thymectomy was performed. No tumor infiltration was observed in the right brachiocephalic vein. No abnormality was found in either phrenic nerve. The tumor could be safely resected, and her postoperative course was uneventful. The pathological diagnosis was a thymoma.

A case of thymectomy with IPLSVC is quite rare. A careful observation of the preoperative computed tomography images helps to diagnose IPLSVC. Technically, thymectomy was not much different from normal, other than the reversed location of the veins. However, it should be noted that IPLSVC cases may have cardiac malformations.

Thymectomy for thymoma with IPLSVC can be safely performed when the left and right veins are reversed.