[An autopsy case of penetration of a sigmoid colon diverticulum with septic shock during the treatment of lung cancer-related pain].

: A 70-year-old man presented with septic shock and abdominal pain during treatment of pain caused by stage IV lung adenocarcinoma. CT revealed air collection from the retroperitoneum to the muscle around the thigh. Septic shock due to retroperitoneal penetration from the digestive tract was suspected. Despite treatment attempts, the patient died. The autopsy diagnosis was penetration of a sigmoid colon diverticulum under the serosa. When a diverticulum is located near the mesenterium and the size of penetration is small, the air collection rather than fecal matter is likely to extend retroperitoneally. Abdominal pain is little manifest in the penetration in contrast to perforation into abdominal cavity, and the attention is needed.