Giant Calyceal Diverticulum in a Child with Solitary Kidney: A Rare Experience.

Calyceal diverticuli are rare entities which are difficult to diagnose radiologically as they mimic various other pathology. Close follow up is essential even in asymptomatic individuals to prevent complications. The authors present a giant calyceal diverticulum in a solitary kidney in a child that was managed by open surgery. Copyright:

INTRODUCTION

Calyceal diverticulum is a rare entity, diagnosed incidentally on intravenous urogram (IVU) in 0.21%–0.06% of adults and children.[1] Febrile urinary tract infection (febrile-UTI) is the most common complaint in symptomatic children.[2] Majority can be followed up with conservative management, however may require treatment for various complications such as stone, infection, abscess, or symptomatic enlargement.[2] Here, we report the case of a 7-year-old boy who presented with UTI due to a large calyceal diverticulum related to the lower calyx of a solitary left kidney. He was successfully managed by open surgery.

CASE REPORT

A 7-year-old male patient presented with the complaint of right lower quadrant abdominal pain associated with low-grade fever for 2 days. There was a preexisting history of constipation. Physical examination was unremarkable, and he underwent a workup for fever which revealed a leukocytosis of 11,200/mm3 and 4–8 pus cell/high-power field on urine examination. An ultrasonography of the abdomen revealed a 12 cm × 10 cm, clear cyst occupying the lower pole of the left kidney. The right kidney was not visualized. The right iliac fossa was normal. Renal function tests were normal. A contrast-enhanced computed tomography abdomen showed a cystic lesion occupying most of the lower pole of the left kidney with the ureter stretched over the cyst [Figure 1a]. The upper pole of the kidney appeared normal. The right kidney was absent. Urine culture grew Escherichia coli sensitive to fluoroquinolone and cefixime, and the child was started on cefixime and stool softener, which led to resolution of the fever and abdominal pain. Subsequent technetium99m diethyl triamine penta-acetic acid (Tc99m DTPA) imaging revealed a photopenic lesion in the lower pole of the left kidney which gradually filled over time, with nonobstructive drainage, and an absent right kidney. Micturating cystourethrogram was normal. A provisional diagnosis of a simple renal cyst or a calyceal diverticulum was considered. In view of the UTI and the presence of a solitary kidney, definitive treatment was planned. The parents were counseled thoroughly and the child was taken up for retrograde pyelography (RGP) and exploration, with the aim of preserving all renal parenchyma. Cystoscopy revealed absent right ureteral orifice. The left ureteral orifice was cannulated and RGP was done. A small ventral jet was visualized from the lower calyx filling up the cyst, confirming the diagnosis of a calyceal diverticulum [Figure 1b]. The kidney was exposed by the left subcostal extraperitoneal approach, and the large diverticulum contained within the paper-thin parenchyma was revealed [Figure 2]. The ureter was stretched out over the cyst. The cyst was opened, the communication with the calyx was identified and ligated, and the floppy cyst wall was excised where the renal parenchyma could be seen (marsupialization). A drain was left and the wound was closed. The postoperative recovery was unremarkable, with the drain removed after day 3 and the child was discharged on the 5th day on urinary prophylactic antibiotics. On follow-up, the child has had normal renal functions with sterile urine at 3 and 6 months and normal blood pressure, and he remains on follow-up with a pediatric nephrologist.

Figure 1

(a) Contrast-enhanced computed tomography of the abdomen showing cystic lesion occupying the lower pole of the solitary left kidney with ureter stretched over it. (b) Retrograde urethrogram: Solid black arrow: Jet of contrast into the diverticulum. Solid white arrow: Diverticulum gradually opacifying

Figure 2

Operative photograph showing the giant diverticulum with thinned-out renal parenchyma

DISCUSSION

Calyceal diverticulum is a nonsecretory transitional epithelial lined outpouching occurring within the renal parenchyma that usually has a communication with the renal collecting system, allowing for passive filling with urine. The actual cause of their origin is not known, however the embryologic theory of alterations of normal branching and interaction between the ureteric bud and metanephric blastema seems to be acceptable, although acquired causes have also been suggested.[1] It may be associated with vesicoureteral reflux.[2] Calyceal diverticulum is mainly of two types: type one has communication with a minor calyx or calyceal fornix and is mostly seen in the region of the upper pole, whereas type two has a communication with the pelvis itself, may attain a large size, and is found in the interpolar region.[134] Most of the children when symptomatic present with UTI. Abdominal pain and hematuria are other common manifestations.[2] In adults, approximately 50% present with stone, which is attributed to stasis in these diverticula.[4] When identified incidentally, they need to be followed up regularly, to rule out stone formation and rapid enlargement in size. Approximately 43% of children may require treatment for the diverticulum on follow-up.[2] Diagnosing the calyceal diverticulum radiologically remains a challenge. Computed tomographic urogram with excretory phase and IVU can be diagnostic, showing passive filling from the collecting system in the delayed film and may demonstrate the communication. Ultrasound scan may show a parenchymal cyst with mobile echogenic material inside, which is characteristic.[35]

Tc99m DTPA can demonstrate the functional delayed filling of the cyst, and magnetic resonance urogram should also be able to diagnose the communication.[5] In ambiguous cases, and for confirmation, RGP is very helpful.[5] Treatment of symptomatic calyceal diverticula depends on the location and anatomy of the diverticula and stone burden in it. A posteriorly situated diverticulum is well suited for percutaneous intervention. The anterosuperior ones can be managed with ureteroscopic interventions and for lower and interpolar regions, laparoscopy or robotic interventions may be well suited, especially if there is a thin parenchyma above a large diverticulum,[4] like that of our case.

In conclusion, calyceal diverticula are rare and interesting anomalies, which have a large number of differential diagnoses and need careful investigations for elucidation. Fortunately, the large majority are small, and many are asymptomatic and need only follow-up. Treatment of the condition will vary according to the nature of presentation, position, and type of diverticulum apart from the availability of technology and expertise. The presented case is singular because of its large size and its presence in a solitary kidney.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.