This rare case is an unusual form of ectopic kidney in an unusual site in a 4-year-old male child presenting with a history of a lump on the dorsal shaft of the penis since birth. He had a history of repeated UTI and failure of growth. Lump size was small at birth, as mentioned by his parents, and increased in size gradually until the last days when there was a noticable increase in size, with redness of the overlying skin and urine retention after complete investigations and full imaging studies. After a cystoscopy and surgical excision, the diagnosis of ectopic kidney on the penile shaft became clear.
Muhammad Abdullah Rahman Alshwani
Submitted December 7, 2011 - Accepted for Publication January 12, 2012
KEYWORDS: Ectopic kidney, congenital anomalies
CITATION: UroToday Int J. 2012 June;5(3):art 22. http://dx.doi.org/10.3834/uij.1944-5784.2012.06.09
Simple congenital ectopy usually refers to a low kidney on the proper side that failed to ascend normally; its incidence is about 1/1 000 per newborn. It may lay over the pelvic brim or in the pelvis. It may rarely be found in the chest. It takes its blood supply from the adjacent vessels and its ureter is short. It is prone to ureteral obstruction and infection, which may lead to pain or fever. At times such a kidney may be palpable, leading to an erroneous presumptive diagnosis (e.g., cancer of the bowel, appendicular abscess). Excretory urography reveals the true position of the kidney. Hydronephrosis, if present, will be evident, and there is no redundancy of the ureter as in the case of acquired ectopy. Obstruction and infection may complicate simple ectopy and should be treated by appropriate means [1,2].
A 4-year-old male child presented with a history of a lump on the dorsal shaft of the penis since birth and a history of repeated UTI and growth failure. The lump was small at birth as mentioned by the patient’s parents and increased in size gradually until the last days when there was a noticeable increase in size, with redness of the underlying skin and urine retention. When seen by a general surgeon, he thought that the case seemed to be an abscess. After incision and drainage and insertion of a Foley catheter, the patient was referred to our urological unit. The child looked healthy. He was febrile with normal hemoglobin and renal function tests. The patient had an elevated WBC count of 10 000, and pyeuria was obvious in the urine exam. The mass was on the dorsal side of the penile shaft and was freely mobile in all directions. An abdominal ultrasonography revealed no kidney in both loins and a solitary kidney at the pelvic brim while the mass on the penile shaft looked kidney-like. An intravenous urography reveled a solitary kidney that was centrally located over the pelvic brim, malrotated, with no evidence of function in the mass. During cystourethroscopy, only the right ureteric orifice was identified while the left orifice was not found even in the urethra. A retrograde urography showed only 1 pelvic kidney. During exploration, the mass was attached to the corpora cavernosa and the suspensory ligament of the penis. A nehprectomy was performed without injury to the corpora and the suspensory ligament. The kidney was grossly and severely hydronephrotic with parenchymal thickness loss. The histopathology showed the mass was truly a kidney with signs of chronic pyelonephritis. The postoperative period passed smoothly, the Foley catheter was removed, and the patient passed urine normally.
It is possible for this condition to go unnoticed as it may not cause any symptoms and may remain undiscovered until the individual has some form of testing done, typically for another medical condition . Many individuals do not experience any issues with this type of birth defect; however, others can develop problems involving the urinary tract such as urinary stones, urinary blockage, or infections . Treatment depends on the severity of the condition and what symptoms are present. If there is no blockage and the child is not developing stones or infections, no treatment is generally necessary. Surgery is necessary if there is an obstruction present or if kidney damage is severe [5-7]. Once renal ectopia is suspected or diagnosed, every attempt should be made to locate the contralateral kidney, as damage or removal of a solitary ectopic kidney may lead to renal insufficiancy, which may necessitate dialysis or transplantation . Gleason et al.  conducted a retrospective review of 77 patients with 82 ectopic kidneys. Out of 82 kidneys, 46 (56%) had hydronephrosis. Dilatation of the renal pelvis was the result of primary ureteropelvic or ureterovesical obstruction in 52%, grade 3, 4, or 5 vesicoureteral reflux in 26%, and extrarenal collecting systems with malrotation that produced apparent ureteropelvic junction obstruction in 22%. Bader et al.  reported that they have initially misinterpreted a case of ectopic pelvic kidney as bulky lymph node conglomerates in 2 different patients undergoing surgery for a gynecological malignancy. They stressed that initial exploration of the abdomen and pelvis after laparotomy should include manual confirmation that the kidneys are in the normal position.
The ectopic kidney is usually smaller than normal, and it may not conform to the usual reniform shape because of the retained fetal lobulations and the axis of the kidney medial or vertical, but it may be tilted as much as 90° laterally so that it lies in a true horizontal plane, so the renal pelvis is usually anterior to the parenchyma . The ectopic kidney is more susceptible to the development of hydronephrosis or urinary calculus formation than the normally positioned kidney; this is in part a result of the anteriorly placed pelvis or an anomalous vasculature that partially blocks one of the major calyces or the upper ureter. In addition, there may be an increased risk of injury from blunt abdominal trauma because the low-lying kidney is not protected by the ribcage [9,10].
In a review of the literature it was discovered that ectopic kidney may be found in a low position in the loin, pelvic bream, and pelvis, and extremely rare cases have been in the chest, but none until now reported a kidney in the penile shaft. It is possible this is the first reported case. Our colleague, who received the case for the first time before its presentation to our unit, believed he drained an abscess but really drained a hydronephrotic kidney. Ectopia of an organ has great importance, especially from a surgical point of view. The possibility of an ectopic kidney should be kept in mind in order to prevent the devastating consequences due to a missed diagnosis. Ectopic positioning and varied vasculature can predispose one to iatrogenic trauma during interventional radiological and surgical procedures. Nephrectomy in our case was indicated because of repeated urinary tract infection and the site of the ectopic kidney, which was vulnerable to trauma.
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