Necrotising fasciitis of the thigh secondary to colonic perforation: the femoral canal as a route for infective spread.

A 57 year-old man with a history of corticosteroid use presented with abdominal pain and diarrhoea. He was initially treated for presumed Clostridium difficile colitis, but later developed a left inguinal mass with spreading erythema. A CT scan showed gas within the retroperitoneal tissues, with surgical emphysema of the left groin. Necrotising fasciitis was diagnosed, and the patient underwent extensive debridement of the left thigh and inguinal region. The femoral vein was covered in infected fascia in the femoral canal, and a laparotomy revealed a posterior perforation of the sigmoid colon. Necrotising fasciitis of the thigh is a rare complication of colonic perforation. Our case highlights the femoral canal as a potential channel for the spread of intra-abdominal infection into the thigh.