S4872 Enterolith-Associated Enterocutaneous Fistula in Ulcerative Colitis: A Rare Complication

Introduction: Ulcerative colitis (UC) is a chronic inflammatory disorder usually confined to the colonic mucosa. Medically-refractory UC is managed with total proctocolectomy with ileal pouch-anal anastomosis. While most have good functional outcomes, rare complications like enterolith formation can lead to enterocutaneous fistula. Enteroliths are rock-like hard deposits in the lumen of the gastrointestinal tract, often caused by intestinal stasis, tumours, tuberculosis, and kinking due to adhesions, among various other causes. We report a rare case of chronic enterocutaneous fistula due to enteroliths in a patient with IBD-UC, 22 years after total colectomy with ileostomy. Case Description/Methods: A 55-year-old man with a history of UC status-post total colectomy with ileostomy presented with a 4-day history of umbilical pain, intermittent stomal bleeding, and fecal discharge with greenish-yellow pus from an umbilical wound. Discharge aggravated with food intake from both sites. He also reported redness and itching around the wound, which was relieved by topical ointments. Physical examination revealed a stoma bag at the RIF end-ileostomy, and a fistulous opening at the umbilicus with fecal drainage; mild tenderness was also noted. Routine labs revealed high C-reactive protein. Abdominal contrast-enhanced computed tomography showed a 6.4 × 6.3 mm enterocutaneous fistula, a 14 mm circumferential irregular wall thickening of mid and distal ileal loops near the fistula, and a gallstone. Enteroscopy revealed 2 linear ulcers and 2 black calculi at 22 cm and 25 cm, measuring 2 × 2 cm and 1 × 1 cm respectively. Enteroliths were removed with Roth’s net. Biopsies confirmed ulcerated ileal mucosa with neutrophilic and lymphocytic infiltrates in the lamina propria with no evidence of granulomas. Discussion: Enterolithiasis is rare, with a prevalence of 0.3% to 10%. Mortality is low in uncomplicated cases but can rise to 3% with delayed diagnosis or obstruction in debilitated patients. Crohn’s disease and intestinal tuberculosis are the most common causes; enteroliths are rare in ulcerative colitis (UC). Fistulas are also uncommon in UC and are typically perianal when present. This case is unusual, as a persistent enterolith led to a chronic enterocutaneous fistula in a UC patient—an atypical complication. Primary enteroliths remain a rare entity, mostly reported in isolated cases involving bowel obstruction. This case highlights an uncommon presentation that broadens the differential diagnosis for fistulizing disease in UC.