Anomalous atrium associated with persistent left superior vena cava.

Persistent left superior vena cava (PLSVC) is the most common venous anomaly with an incidence of 0.3-0.5% in the general population. Here, we report a rare case of PLSVC with anomalous atrium in a cadaver during the student's dissection session at the University of Tsukuba. In this case, the coronary sinus had merged with the right atrium to form an enlarged sac-like structure and received systemic venous flow including inflow from the PLSVC. The roof of the coronary sinus with the right atrium was thicker than that of the control cases. We further found that the distance between the sinoatrial node and the opening of the coronary sinus was slightly more than half of that in control cases. This variant appears interesting and is worth reporting for developmental and clinical consideration.