Horseshoe kidney with extrarenal calyces and malformed renal vessels

The horseshoe kidney is a congenital fusion anomaly where both kidneys are fused at the lower poles. We report a case of horseshoe kidney in a 70 year-old Thai cadaver. This horseshoe kidney was associated with malformations of renal hila, sinuses, calyces and supernumerary arterial supplies from the dorsal part of the kidney. To our knowledge, the arterial supply to the horseshoe kidney from the dorsal aspect has never been reported. Dissection revealed six aberrant renal arteries directly originated from the abdominal aorta supplying directly the renal segments. We believe that it was probably due to the persistence of mesonephric arteries. Also, the ascension of the horseshoe kidney in the present case was restricted by one of the renal arteries, not the inferior mesenteric artery. The embryology, anatomy, and the clinical significance of the present case are discussed.