PT - JOURNAL ARTICLE AU - Carolyn Cullinane AU - Helen Earley AU - Shona Tormey TI - Deadly combination: <em>Clostridium septicum</em> and colorectal malignancy AID - 10.1136/bcr-2017-222759 DP - 2017 Dec 02 TA - BMJ Case Reports PG - bcr-2017-222759 VI - 2017 4099 - http://casereports.bmj.com/content/2017/bcr-2017-222759.short 4100 - http://casereports.bmj.com/content/2017/bcr-2017-222759.full AB - Gas gangrene is a life-threatening, necrotising soft tissue infection. Colorectal malignancy-associated Clostridiumsepticum is a rare cause of gas gangrene. This case outlines an initial presentation of colonic malignancy as gas gangrene from C.septicum infection.A 69-year-old man presented with abdominal pain, vomiting and constipation. Abdominal X-ray revealed dilated small bowel loops. Lactate was elevated. A diagnosis of small bowel obstruction was made. Subsequent CT revealed caecal thickening and subcutaneous emphysema overlying the left flank. Clinically, he became haemodynamically unstable. Examination revealed crepitus overlying the left flank in keeping with gas gangrene. The patient required immediate surgical debridement. Tissue specimens cultured C.septicum. Following a complicated postoperative period, he was transferred to the plastic surgery team for further tissue debridement and reconstruction. A colonoscopy was later performed which was suspicious for malignancy. Colorectal multidisciplinary team discussion is awaited.