Recurrent retroperitoneal abscess due to perforated colonic diverticulitis in a patient with polycystic kidney disease.

Patients with autosomal dominant polycystic kidney disease (ADPKD) usually have extrarenal manifestations. We report the case of a 53-year-old man with ADPKD who presented with a retroperitoneal abscess of the left side after undergoing bilateral nephrectomy for a cyst that had repeatedly bled for 1 year. The abscess recurred despite drainage with a pig-tail catheter and antibiotic treatment. Fistulography with injection of diluted contrast medium via the pig-tail catheter showed an accumulation of contrast medium in the descending colon, which indicated a fistula between the abscess and the descending colon. A portion of the descending colon was resected, and multiple diverticulitis with 1 perforation in the resected specimen was observed. The findings support a diagnosis of retroperitoneal abscess caused by a perforated diverticulum---an extrarenal manifestation of ADPKD.