Asian Journal of Case Reports in Surgery

Colocutaneous fistula is an abnormal communication between the colon and the skin. It is uncommon and is most often associated with previous surgery, inflammatory bowel disease, diverticulitis, malignancy, tuberculosis or radiation-related bowel injury. Spontaneous colocutaneous fistula is rare and may indicate an underlying advanced inflammatory or malignant process. This report describes two male patients who presented with faeculent discharge from the right flank. The first patient was a 57-year-old man with chronic right lower abdominal pain, weight loss, intermittent constipation, bleeding per rectum and a faeculent opening over the right posterolateral abdominal wall. Contrast-enhanced computed tomography showed bowel wall thickening with a sinus tract extending to the abdominal wall. Colonoscopy revealed an ulceroproliferative growth in the proximal ascending colon, and biopsy confirmed moderately differentiated adenocarcinoma. He underwent right hemicolectomy with excision of the fistulous tract. The second patient was a 43-year-old man with recurrent right flank discharge, fever, reduced appetite, loose stools and multiple external openings. Imaging showed terminal ileal and ileocaecal thickening with an intra-abdominal abscess and fistulous tracts extending to the skin. Exploratory laparotomy and ileostomy were performed, and histopathology favoured Crohn’s disease. These cases highlight that spontaneous colocutaneous fistula should prompt evaluation for malignancy and inflammatory bowel disease. Early imaging, sepsis control, nutritional optimisation, definitive surgery and appropriate postoperative medical management are important for favourable outcomes.