A Case of Horseshoe Kidney / 체질인류학회지

ABSTRACT

During cadaver dissection at Chungnam National University in year 2001, we found a case of horseshoe kidney. The characteristic findings of this kidney were as follows; 1. Horseshoe kidney was located at the level of 12th thoracic vertebra and 4th lumbar vertebra, and its isthmus was located at the level of 3rd lumbar vertebra, just below inferior mesenteric artery. The upper pole of the right kidney was 11 mm higherthan that of left kidney. 2. Both renal arteries originated normally from the abdominal aorta below superior mesenteric artery and divided into 2 branches at the front of the renal hilum. The lower branches entered normally into the renal hilum respectively, but, 2 upper branches of right renal artery and 3 upper branches of left renal artery entered into the upper segment of both kidneys respectively. 3. The 2 accessory renal arteries were found. One was the branch of the median sacral artery, which asended anterior to the bifurcation of abdominal aorta and divided 2 branches, of which larger right branch entered inferior pole of right kidney and smaller left branch entered into the isthmus. The other was originated from abdominal aorta 1/3 distance from the origin of inferior mesenteric artery to the bifurcation of abdominal aorta, and entered into the posteroinferior part of left kidney. 4. There were additional 2~3 minor calyces in the lower part of the both kidneys in frontal section, which formed a major calyx draining into the renal pelvis. Parenchymal tissues of both kidneys were continuous through isthmus. In frontal section, renal pyramids were twice in number, and arranged into 2 groups at the upper and lower parts of the both kidneys. Especially, one renal pyramid laid transversely in the isthmus and the renal papilla of it opened into the minor calys of left kidney. It is thought that this horseshoe kidney might be resulted from the elongation of a ureteric bud, which induced new broad -field nephron within the metanephric blastema, and formed a group of additional renal pyramids. The additional renal pyramids formed slight later than normal period, and the separation of both kidneys should be failed and resulted horseshoe kidney. During ascent of kidney, the inferior mesenteric artery interrupted upward migration. It can be concluded that the error of reciprocal induction between ureteric bud and metanephric mesenchyme may be an important mechanism of horseshoe kidney formation.