A Potential Link: Cross-fused Renal Ectopia With Concomitant Absent Left Testicle

Case Review A Potential Link: Cross-fused Renal Ectopia With Concomitant Absent Left Testicle David W. Drevna, MD, Joseph Dankoff, MD, Bryant Van Leeuwen, MSIV Cleveland Clinic Akron General Urology Residency Program, Akron, OH Cross-fused renal ectopia (CFRE) is a rare congenital anomaly in which both kidneys are located on a unilateral side of the retroperitoneal space. The ureter of the ectopic kidney is seen to pass over the midline to insert in its normal anatomic position. Frequently this anomaly goes undetected until there is radiologic screening for other purposes or when other genitourinary issues are investigated. Although frequently isolated, this condition has been reported to be associated with other congenital anomalies, genetic disorders, and various urogenital anomalies more than 50% of the time. However, we found no cases linking CFRE with a solitary testicle. This is a case of a 30-year-old man with left-to-right CFRE with concomitant absent left testicle and obstructing distal calculus. [Rev Urol. 2018;20(1):49–51 doi: 10.3909/riu0770] ® © 2018 MedReviews, LLC KEY WORDS Cross-fused renal ectopia • CFRE C ross-fused renal ectopia (CFRE) is a rare congenital anomaly in which both kidneys are located on a unilateral side of the retroperitoneal space. The ureter of the ectopic kidney is seen to pass over the midline to insert in its normal anatomic position. Frequently this anomaly goes undetected until there is radiologic screening for other purposes or when other genitourinary issues are investigated. Although frequently isolated, this condition has been reported to be associated with other congenital anomalies, genetic disorders, and various urogenital anomalies more than 50% of the time.1,2 However, we found no cases linking crossfused renal ectopia with a solitary testicle. This is a case of a 30-year-old man with left-to-right CFRE with concomitant absent left testicle and obstructing distal calculus. Case Report A 30-year-old white man presented to the emergency department with left lower quadrant pain that Vol. 20 No. 1 • 2018 • Reviews in Urology • 49 4170018_12_RIU0770_V1_rev03.indd 49 4/23/18 12:04 PM Cross-fused Renal Ectopia continued radiated to the right flank. He complained of nausea and emesis along with the pain for approximately 10 hours prior to presentation. The patient was found to have mild acute kidney injury with a glomerular filtration rate of 50, which was below his known baseline, and an otherwise normal laboratory workup except for blood on a urinalysis. Subsequently, a computed tomography (CT) scan of the abdomen and pelvis revealed a cross-fused renal ectopia with the lower pole moiety having hydroureternephrosis and a distal ureteral calculus. The radiograph revealed that the lower pole moiety ureter crossed the midline and inserted into the left trigone of the bladder. The upper pole moiety had a separate ureter that was normal in caliber and inserted into the right trigone. Secondary to uncontrolled pain and acute kidney injury, the patient was admitted to the hospital and taken to surgery later that day. Of note, on physical examination the patient had an absent left testicle. He reported having exploratory scrotal surgery as a child wherein the left testicle was never found. Record of a follow-up diagnostic laparoscopy also revealed no leftsided cord structures were identified. The patient denied any other medical issues. During the current surgery it was noted that the patient had a normal appearing bladder and that he had what appeared to be orthotopic inserting right and left ureteral orifices. A retrograde urogram of the left ureteral orifice revealed a distal filling defect consistent with calculi; the path of the lower pole moiety as it crossed the patient’s midline was also visualized (Figure 1). After laser lithotripsy of the calculus, a multi-length ureteral stent was left in place. The patient was subsequently discharged to home in stable condition. Discussion Cross-fused renal ectopia is a rare congenital anomaly only occurring in approximately 0.01% of the population with a male predominance of 3:2.3 During development, the ectopic kidney and ureter cross the midline and the Figure 1. A retrograde urogram of the left ureteral orifice revealed a distal filling defect consistent with calculi; the path of the lower pole moiety as it crossed the patient’s midline was also visualized. fusion malformation second only to horseshoe kidney.4 Six specific variations of this anomaly are described in the lit- Cross-fused renal ectopia is a rare congenital anomaly only occurring in approximately 0.01% of the population with a male predominance of 3:2. parenchyma of both kidneys fuse together. The ureteric bud develops properly, however, meaning each kidney retains its own renal pelvis and normal insertion of the ectopic kidney’s ureter is preserved.1 This gives the malformation its name and classical crossed ureter appearance. Despite its rarity, CFRE is a very common renal erature: inferior cross-fused renal ectopia, superior cross-fused renal ectopia, sigmoid kidney, lump kidney, L-shaped kidney, and disc kidney. The most common of these variations is the inferior CFRE type; the most commonly observed form of this malformation is a left-to-right cross-fused ectopia in which the left ectopic renal unit is Main POintS • Cross-fused renal ectopia (CFRE) continues to be a rare congenital anomaly that is encountered in the urologic community. This condition is associated with multiple genetic disorders and various urogenital anomalies. • A literature search failed to uncover a previously known link between cross-fused renal ectopia and a solitary testicle. The possibility of a previously undocumented, pathogenic association between these abnormalities warrants attention and further investigation. • Care must be taken when dealing with these patients due to their aberrant anatomy, especially in terms of the renal unit’s vasculature and the course of the ureter crossing the midline. 50 • Vol. 20 No. 1 • 2018 • Reviews in Urology 4170018_12_RIU0770_V1_rev03.indd 50 4/23/18 12:04 PM Cross-fused Renal Ectopia fused to the lower pole of the right moiety within the right retroperitoneal space.4 Most often, patients with CFRE are asymptomatic and most have an excellent prognosis without intervention. Frequently this anomaly goes undetected and is coincidentally discovered with radiologic screening for other purposes or when other genitourinary issues are investigated, leading to radiographs or surgical intervention. With advancing ultrasound technology it is now also being routinely discovered on antenatal ultrasound.5 The most common urologic abnormality found in CFRE is vesicoureteral reflux with grade 2 or greater reflux occurring in approximately 20% of patients.6 Up to half of all patients will eventually have some form of urological complication, including obstructing renal calculi (as seen in our case), hydronephrosis, or frequent urinary tract infections.1 What makes our case unique is the concomitant absent left testicle. The cause of CFRE is uncertain with the two most common theories being a genetic versus developmental (overbending and rotation of the caudal end of the developing embryo) cause.1 CFRE has been associated with other VACTERL congenital malformation. It is also associated with other genitourinary abnormalities warrants attention and further investigation. Care must be taken when dealing with these patients due to their Our case, to our knowledge, is the first documented case of CFRE with a completely absent left testicle. The possibility of a previously undocumented, pathogenic association between these abnormalities may provide a link for further research into the cause of CFRE. defects, specifically cryptorchidism and hypospadias.7 Our case, to our knowledge, is the first documented case of CFRE with a completely absent left testicle. The possibility of a previously undocumented, pathogenic association between these abnormalities may provide a link for further research into the cause of CFRE. aberrant anatomy, especially in terms of the renal unit’s vasculature and the course of the ureter crossing the midline. Although many of these cases are never discovered until autopsy, this proves to be an interesting case in a patient with a concomitant absent left testicle. Conclusions 1. CFRE continues to be a rare congenital anomaly that is encountered in the urologic community. This condition is associated with multiple genetic disorders and various urogenital anomalies. However, our literature search failed to uncover a previously known link between CFRE and a solitary testicle. The possibility of a previously undocumented, pathogenic association between these References 2. 3. 4. 5. 6. 7. Rinat C, Farkas A, Frishberg Y. Familial inheritance of crossed fused renal ectopia. Pediatr Nephrol. 2001;16:269-270. Bhatt K, Herts BR. Crossed fused renal ectopia. J Urol. 2014;191:475-476. Patel TV, Singh AK. Crossed fused ectopia of the kidneys. Kidney Int. 2008;73:662. Solanki S, Bhatnagar V, Gupta AK, et al. Crossed fused renal ectopia: challenges in diagnosis and management. J Indian Assoc Pediatr Surg. 2013;18:7-10. Glodny B, Petersen J, Hofmann KJ, et al. Kidney fusion anomalies revisited: clinical and radiological analysis of 209 cases of crossed fused ectopia and horseshoe kidney. BJU Int. 2009;103:224-235. Guarino N, Tadini B, Camardi P, et al. The incidence of associated urological abnormalities in children with renal ectopia. J Urol. 2004;172:1757-1759. Kelalis PP, Malek RS, Segura JW. Observations on renal ectopia and fusion in children. J Urol. 1973;110:588-592. Vol. 20 No. 1 • 2018 • Reviews in Urology • 51 4170018_12_RIU0770_V1_rev03.indd 51 4/23/18 12:04 PM