Ectopic kidney

Abstract: C ROSSED renaI ectopia is an uncommon anomaIy of the urinary tract, occurring once in every 7,000 autopsies [I]. In order to deveIop the clinical and radiographic picture of this condition further, a full review of the literature and a report of two cases 41 be presented. Crossed renal ectopia is a congenital condition in which a ureter in the norma bladder position crosses the midline to an ectopic kidney Iying on the opposite side of the body. This anomaly may be divided into four types (Fig. I) : Crossed Renal Ectopia with Fusion. This type is the most common of the four. (Fig. IA.) Abeshouse [2] in 1947 reported four cases and coIIected forty-seven reported since Wilmer’s review [j] in 1938, bringing the tota number to 337. Twenty-six cases have been collected since 1947 in addition to thirteen cases published prior to that year [d-343 and not included in the review by Abeshouse. In the absence of definite knowledge of the presence of fusion, our two cases have aIso been placed in this group. This ectopic form is characterized by fusion of the ectopic and normally positioned kidney. The resuIting renaI mass varies in anatomic form depending on the portion of the kidneys involved in the fusion. Six different forms of this anomaIy have been described. In all these forms axial rotation of both kidneys is impeded with the pelves located anteriorly. (Table I.) The most common form is the unilateral ,fused kidney with the ectopic kidney injerior. (Fig. 2A.) Second in frequency is the S-shaped or sigmoid kidney. This varies from the aforementioned in the degree of axia1 rotation of the ectopic kidney in reIationship to the norma kidney. (Fig. 2B.) The third form is the lump kidney. This is reIativeIy uncommon and is characterized by the extensive fusion of the two kidneys resulting in a soIid, irreguIar renal mass. The kidney mass is usuaIIy Iocated just above, or at the IeveI of, the sacra1 promontory. (Fig. 2C.)