Necrotising fasciitis secondary to a colocutaneous fistula

Colocutaneous fistulae secondary to diverticular disease are rare, especially spontaneous fistulae. We report a case of a 74-year-old lady, with no previous history of diverticular disease, presenting with necrotising fasciitis of the anterior abdominal wall in the left iliac fossa, without any other symptoms. Urgent surgery was performed. An initial diagnostic laparoscopy demonstrated a perforated sigmoid diverticulum forming a fistula to the anterior abdominal wall. Following soft tissue debridement, a sigmoid colectomy was performed through a midline laparotomy. Gastrointestinal pathology should be considered as a potential cause of abdominal wall necrotising fasciitis. Our approach of using laparoscopic visualisation to assess for intra-abdominal sources in this context (in the absence of preoperative imaging when imaging could delay treatment) has not been described before. To our knowledge, only two cases of abdominal wall necrotising fasciitis secondary to diverticular disease with a colocutaneous fistula have been reported in the English literature.