S3787 Foreign Body-Induced Diverticular Abscess in a Patient Without Recent Surgery: A Rare Surprise

Introduction: Diverticulitis is a common gastrointestinal condition with a wide spectrum of clinical severity. While most cases respond to conservative management, complications such as abscess formation occasionally require surgical intervention. Rarely, foreign bodies can serve as a nest for infection. We present a unique case of complicated diverticulitis with an intraperitoneal abscess ultimately found to contain a foreign body of unclear origin. Case Description/Methods: A 65-year-old woman with a history of hypertension and hyperlipidemia presented with left lower abdominal pain for 2 days. Laboratory evaluation revealed leukocytosis (WBC 13,000). Computed tomography (CT) imaging showed acute sigmoid diverticulitis with an abscess measuring 3.1 × 5.9 cm. She was started on IV ceftriaxone and metronidazole, but her symptoms and inflammatory markers worsened over the next 3 days. General surgery performed laparoscopic drainage and washout with drain placement. Despite this, the patient remained febrile with an increasing WBC count. Antibiotics were escalated to piperacillin-tazobactam. Repeat CT showed persistent sigmoid diverticulitis with a collection measuring 4.0 × 4.2 × 3.3 cm. A second laparoscopic procedure was done, during which a foreign body was visualized and removed. Air leak testing via proctoscopy revealed no perforation. Pathologic analysis identified the object as a circular plastic ring 0.5 cm in diameter. Her prior surgical history included an appendectomy 15 years ago and a tubal ligation 20 years ago. She recovered well postoperatively. Discussion: This case highlights an unusual instance of diverticulitis complicated by a retained intra-abdominal foreign body. The origin remains uncertain. One possibility is a remnant from remote intra-abdominal procedures such as tubal ligation or appendectomy, lying dormant until inflammation from diverticulitis triggered a localized reaction. Alternatively, the foreign body could have been introduced during the initial laparoscopic drainage, although this is exceedingly rare with modern surgical technique. Regardless of origin, the presence of a retained plastic ring in the pericolic abscess created diagnostic ambiguity and therapeutic difficulty. This case underscores the importance of maintaining a broad differential in patients with atypical or refractory diverticulitis and emphasizes the role of repeat surgical exploration in cases failing standard treatment. To our knowledge, this is a rare presentation not previously described in the literature.