Urinoma in a young child 6 months following dual cadaveric renal transplantation detected on technetium-99m ethylene dicysteine renal dynamic scan confirmed on SPECT/CT

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An 8-year-old male child, who received two cadaveric kidney transplants in a single sitting 6 months earlier, developed decreased urine output with pain in lower abdomen. A fluid collection was noticed in the pelvic cavity below the allografts and superolateral to the urinary bladder on ultrasound while technetium-99m ethylene dicysteine renal dynamic scan revealed normal perfusion [Figure 1] and parenchymal uptake of tracer. It also demonstrated a photopenic region in the right iliac fossa below the transplanted kidneys [Figure 1] that gradually filled up with the radiotracer in the 3 h delayed static images [Figure 2]. Single-photon emission computed tomography/computed tomography revealed a large tracer filled collection abutting the bladder and displacing it to the left [Figure 3]. Although several cases of post kidney transplant urinomas have been previously reported in literature, to the best of our knowledge, the latter complication in pediatric patients with dual cadaveric renal transplant occurring 6 months after the surgery has not been published.

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Figure 1 Technetium-99m ethylene dicysteine renal dynamic scan revealed normal perfusion and parenchymal uptake of tracer. It also demonstrated a photopenic region in the right iliac fossa below the transplanted kidneys

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Figure 2 The photopenic area seen in Figure 1 gradually filled up with the radiotracer in the 3 h delayed static images

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Figure 3 Single-photon emission computed tomography/computed tomography revealed a large tracer filled collection abutting the bladder and displacing it to the left

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Urine leaks and urinomas are relatively rare complications of renal transplantation and usually present in the early post-operative period. Isa et al.,[1] in their study have reported the complication in less than 10% cases of cadaveric kidney transplant. The majority (about 80%) of these presented within 90 days of transplant. Our patient developed an urinoma 6 months after the surgery. Routh et al.,[2] studied the pattern of urologic complications in pediatric population and found no association of the former with the donor type (living or deceased) and patient's age. Most fluid collections after renal transplantation are incidental findings on baseline ultrasound examinations and require no treatment.[3] Extravasation of urine may occur from the renal pelvis, ureter, or ureteroneocystostomy site. The cause may be an unidentified injury to the pelvis/ureter during transplant surgery itself or due to late ureteral necrosis caused by vascular insufficiency or increased urinary pressures caused by obstruction. Urinomas vary in size and are usually found between the transplanted kidney and the bladder. They may occur, however, in unexpected locations such as the scrotum or thigh. Large urinomas can rupture to produce urinary ascites. They can also become infected and eventually form abscesses. Thus, early detection and repair have been instrumental in graft preservation and reducing patient mortality. Nuclear medicine imaging may thus play an important role in confirming the diagnosis early in the course.