Tandem Kidney: A Case of Left Crossed Fused Renal Ectopia

Crossed fused renal ectopia is a condition in which the ureter of one kidney enters the urinary bladder on the opposite side. It is the second most frequent fusion abnormality of the kidney after the horseshoe kidney. The crossed kidney is horizontally fused to the lower pole of the normal kidney in the case of tandem kidney, which is a kind of crossed fused renal ectopia. A 33-year-old woman was diagnosed with pelvic inflammatory disease and a urinary tract infection. She was found to have left crossed renal ectopia with a Tandem kidney subtype during her ultrasonography assessment. Crossed fused renal ectopia may be asymptomatic, associated with other anomalies such as hydronephrosis, or represent a risk factor for renal neoplasms. It has been associated with genital and anorectal malformations. Fused renal abnormalities are of significance during abdominal surgeries such as malignant kidney excision, renal transplantation, or surgical management of aortic aneurysm. Keywords: Ectopic kidney, Crossed renal ectopia, Tandem kidney, Horseshoe kidney