Necrotizing fasciitis is recognized as a surgical emergency. Early detection and aggressive surgical débridement are crucial to reduce patient mortality and morbidity. There are, however, other causes of subcutaneous emphysema. We present the case of a 64 year-old patient with a history of postsurgical radiation for rectal carcinoma with subcutaneous emphysema of the thigh in the presence of urinary sepsis. Surgical exploration revealed the source of the emphysema to be an enterocutaneous fistula. The patient had an unstable and prolonged hospitalization after débridements of the thigh and abdominal surgery and was readmitted for recurrence of thigh drainage, but eventually was discharged; nine months after the initial diagnosis all wounds had healed and he was walking with a walker. Despite an otherwise benign clinical appearance, the radiographic finding of subcutaneous emphysema in the absence of penetrating trauma must be considered a case of a necrotizing soft tissue infection until proven otherwise.