Crossed renal ectopia.
BJ Birmole, SS Borwankar, AS Vaidya, BK Kulkarni
Dept of Paediatric Surgery, KEM Hospital, Parel, Bombay, Maharashtra.
B J Birmole
Dept of Paediatric Surgery, KEM Hospital, Parel, Bombay, Maharashtra.
A 2 year old male child presented with mass on right side of abdomen. The clinical diagnosis of renal lump was made and rest of the examination did not reveal any abnormality. His intravenous pyelography showed non-functioning left kidney. Cystoscopy and ascending pyelography on left side showed normal ureteric orifices and crossing of the left ureter to opposite side. Ectopic kidney was removed without any damage to the lower pole of the right kidney.
|How to cite this article:|
Birmole B J, Borwankar S S, Vaidya A S, Kulkarni B K. Crossed renal ectopia. J Postgrad Med 1993;39:149-51
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Birmole B J, Borwankar S S, Vaidya A S, Kulkarni B K. Crossed renal ectopia. J Postgrad Med [serial online] 1993 [cited 2023 Jun 2 ];39:149-51
Available from: https://www.jpgmonline.com/text.asp?1993/39/3/149/611
Ninety percent of crossed ectopic kidneys are fused to the ipsilateral kidney. 1 Most patients have concomittant urinary pathology which makes the kidney susceptible to infection and obstruction which ultimately dictate its management. Pediatric patients most often present with unrelated symptoms or the pathology is detected incidentally. We discuss here a case of a child with crossed ectopic kidney and review the available literature.
2-year-old male child presented to our outpatient department with a mass on the right side of the abdomen detected accidentally by his mother. The child was thriving well and had no symptoms related to the urinary tract. On examination there was a well-defined lump in the right lumbar region moving well with respiration. The lump was nontender with a cystic feel medially and firm feel laterally. The bladder was not palpable and genital examination was normal. There was no evidence of any associated anomaly. The clinical diagnosis of renal lump was made. On investigation, blood counts were found to be normal. The urine was normal on microscopic and biochemical examination and grew no organisms on culture. Ultrasongraphy revealed the possibility of a crossed fused ectopic kidney with hydronephrosis. On intravenous pyelography only the right pelvicalyceal system was seen which was normal [Figure:1]. The position of the right kidney was normal while the ureter was shifted too far laterally. There was no reflux on micturiting cysto-urethrography. Cystoscopy and ascending pyelography on the left side showed normal ureteric orifices and crossing of the left ureter to the opposite side [Figure:2]. Renal scan did not show any function in the ectopic kidney.
The patient was operated by a transperitioneal approach. There was L shaped fusion with hydronephrosis of ectopic kidney [Figure:3]. The blood supply of both was from the aorta by a single artery to each. Nephrectomy was performed without any damage to the lower pole of the right kidney or right ureter. Post-operative course was smooth and patient was discharged on the 8th post-operative day. Histopathology revealed segmental renal dysplasia.
The reported incidence of crossed renal ectopia is 1:2000 to 1:7000 autopsies. It was first described by Pannorlus in 1654. McDonald and McClellan 4 classified crossed ectopic kidney into 4 types (i) crossed renal ectopia with fusion, (ii) crossed renal ectopia without fusion, (iii) solitary crossed renal ectopia and (iv) bilaterally crossed renal ectopia.
Those with fusion were further classified by the nature of the fusion and position.
The embryologic etiology of crossed ectopic kidneys is unclear. Some have suggested that the developing kidney crosses to the opposite side.
According to others the ureteral bud alone is responsible for crossing. This is based on the fact that the ureteral pain from stones is felt on the side of the ureteral orifice, whereas renal pain is felt on the side of the kidney. We feel that the presence of dysplasia can be explained by the latter theory as both ureters meet the same nephrogenic cord; one at a site with maximum nephrogenic potential while other with a suboptimal one. Our patient had segmental dysplasia and the kidney was non-functioning inspite of good cortical thickness of around 1.5cm. The dysplasia in a crossed fused ectopic kidneys has been reported rarely.
In 20-30% the pathology is an incidental finding. In the rest the most common symptoms reported are: abdominal or flank pains, a palpable mass, hematuria, urinary tract infection and dysuria. The urological conditions associated with crossed ectopic kidneys are: hydronephrosis, reflux, tumours and nephrolithiasis. Tumours in crossed ectopic kidneys have been reported sporadically. Padiatric patients most often present with multiple congenital anomalies, especially of the skeletal system. A 55% incidence of associated anomalies is reported in a series of 378 cases of crossed fused ectopy. The incidence is highest in regard to solitary crossed ectopy. There is no definite pattern of associated congenital anomalies with crossed renal ectopia, which suggests that the lesion is an acquired defect. Our patient had no other anomaly. The concomittant urinary pathology was pelvi-ureteric junction obstruction with hydronephrosis. The presentation was with a lump.
The diagnosis is made by ultrasongraphy and intravenous urography. Ultrasound can detect concomittant urinary pathology and cystic changes.
Anatomical delineation is best achieved with IVU. Besides function it can give an idea about ureteric displacement. Cystourethrography should be done routinely in all children with renal anomalies of fusion or position. The theory of ureteric bud migration implies abnormality at the lower and giving rise to a high incidence of reflux. In confusing cases when one cannot determine the course of the ureter, a retrograde study is often helpful, ephrectomy is the treatment of choice in case of a crossed ectopic non-functioning kidney realising the fact that the chances of ipsilateral kidney being abnormal are high. The decision of nephrectomy can be supported by a renal scan. The diagnosis and management in our patient was aided by the above investigations.
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