A RARE FORM OF CROSSED-FUSED RENAL ECTOPIA: FUSION ANTERIOR TO THE LEFT ORTHOTOPIC KIDNEY LUIS M. PE ´ REZ, JOSE ´ F. MANIBO, AND JOSE ´ MURILLO B. NETTO A 7-year-old white girl with a history of spina bi- fida and severe kyphosis presented with recur- rent urinary tract infections. Renal ultrasound re- vealed a crossed-fused renal ectopia with both kidneys located in the left renal fossa and the larger kidney fused anterior to the smaller kidney (Figure 1). Voiding cystourethrography during videourody- namic evaluation demonstrated an irregularly shaped neurogenic bladder with bilateral vesicoureteral re- flux. Grade 4 reflux was noted in the right collecting system, which crossed the midline and was the larger anterior renal unit noted in the left renal fossa by renal ultrasound. Grade 3 reflux was noted in the smaller posterior left collecting system (Figure 2). The patient was treated with clean intermittent cath- eterization, prophylactic antibiotics, and anticholin- ergic medication. Several variations of crossed-fused renal ectopias exist. 1 Most cases present with the upper pole of the crossed kidney fusing to the inferior pole of the nor- mally positioned kidney. Furthermore, ectopia usu- ally occurs from a left to right direction, rather than right to left. 1 The case presented herein is unique, since it was an anterior-posterior fusion and the ec- topia occurred from right to left. Crossed-fused renal ectopia occurs more frequently in patients with spi- nal dysraphism (0.8% to 3.3%) than in the general population (0.01% to 0.02%). 2,3 Renal ultrasound, intravenous urography, computed tomography, or magnetic resonance imaging can confirm the diagno- From the Section of Pediatric Urology, Division of Urology, De- partment of Surgery, University of Alabama at Birmingham, Children’s Hospital, Birmingham, Alabama Reprint requests: Luis M. Pe ´rez, M.D., Pediatric Urology, ACC-318, 1700 6th Avenue South, Birmingham, AL 35233 Submitted: February 10, 1999, accepted (with revisions): April 7, 1999 FIGURE 1. Ultrasound of the left renal fossa revealing a larger anterior renal unit fused to a smaller, posterior renal unit. FIGURE 2. Voiding cystourethrography showing a “Christmas tree” bladder and bilateral vesicoureteral reflux (grade 4 in the right anterior renal unit and grade 3 in a smaller posterior left renal unit) to a right-to-left crossed-fused renal ectopia. IMAGES IN CLINICAL UROLOGY © 1999, ELSEVIER SCIENCE INC. UROLOGY 54: 742–743, 1999 • 0090-4295/99/$20.00 742 ALL RIGHTS RESERVED PII S0090-4295(99)00189-2