URETERAL OBSTRUCTION DUE TO COLONIC DUPLICATION

Abstract

Ureteral obstruction due to intrinsic or extrinsic factors is a common clinical occurrence. However, the diagnosis can be difficult, especially with rare etiologies. We report on a patient with renal colic from ureteral obstruction caused by a segmental duplication of the hindgut. CASE REPORT A 24-year-old man presented with acute right flank pain and nausea. He had no history of kidney stones, infections of the urinary tract or hematuria. At age 17 years he had undergone percutaneous drainage of a right psoas abscess, of which the etiology was unclear. He reported intermittent crampy abdominal pain since the early teenage years. On physical examination, the patient was afebrile with normal vital signs. Right costovertebral tenderness was present as well as mild tenderness in the right upper quadrant. Laboratory evaluations, including complete blood count, creatinine and electrolytes, were normal. Urinalysis demonstrated microscopic hematuria without leukocytes, bacteria or crystals. A scout film of the abdomen showed no radiopaque shadows. Excretory urogram revealed obstruction of the proximal right ureter with associated hydronephrosis (fig. 1, A). The patient was referred to us with a diagnosis of a right ureteral stone. Intermittent abdominal cramping and right flank pain were persistent. Right retrograde pyelography showed a normal distal and mid ureter (fig. 1, B). The proximal ureter was dilated and the obstruction appeared to be due to extrinsic compression. A right ureteral stent was placed to relieve the obstruction. Abdominal computerized tomography demonstrated a tubular, thick walled cavity extending from the right retroperitoneal region just anterior to the proximal right ureter, which extended across the midline towards the left colon (fig. 2, A). Differential diagnosis of an abscess or tumor was considered and a barium enema was ordered (fig. 2, B). A blind-ending pouch arising from the splenic flexure, crossing the midline and ending in the region of the right kidney was seen. A large filling defect was near the neck of the pouch. Diagnosis was duplication of the colon causing ureteral obstruction. On surgical exploration the duplicated colonic segment was removed and ureterolysis with omental wrapping of the right ureter was performed. The filling defect seen on barium enema was a massive fecalith in the duplicated hindgut. Pathological examinations revealed all 3 layers of native bowel, which was consistent with a true duplication of the hindgut. Convalescence was uneventful with complete resolution of symptoms. After removal of the ureteral stent, a nuclear renal scan demonstrated normal function of the right kidney without evidence of obstruction.