[A case of persistent left superior vena cava with a horseshoe kidney]

A case of persistent left superior vena cava with a horseshoe kidney was found in a Japanese male cadaver (72 years old) during a dissection for students in 1989. The main findings were as follows. The right superior vena cava (21.2 mm average diameter) was normal and opened into the right atrium. The left superior vena cava (8.4 mm average diameter) was smaller than the right one and ran in the coronary sinus to reach the right atrium. There was a small transverse anastomosis (8.9 mm average diameter), which corresponded to the normal left brachiocephalic vein, between the right and left superior vena cava. The azygos vein system showed a symmetrical condition and the right and left azygos veins opened into the superior vena cava on each side. This was the 57th case of persistent left superior vena cava reported in the anatomical literature in Japan. It corresponded to Type 3 of the classification by Fujimoto et al. (1971), and might be the first report of Type 3 in Japan. The horseshoe kidney was a typical one, in which the right and left kidneys were fused by an isthmus (bridge) consisting of renal tissues at their lower poles. The positions of both kidneys were lower than those of normal ones, the bilateral renal hili opened ventrally, the ureters ran on the anterior surface of the isthmus, the longitudinal axes of both kidneys crossed each other under the isthmus, and there were some additional renal arteries and veins. Neither the persistent left superior vena cava nor the horseshoe kidney alone are very rare anomalies, but a case such as the present, in which both anomalies coexist in the same body, is very rare.