A Case of Transmesosigmoid Hernia

Internal abdominal hernias, which are protrusions of a viscus through a mesenteric or peritoneal defect, are uncommon. Symptom from internal hernias are uncharacteristic and most are diagnosed at laparotomy for ileus. This is a report of a 69-year-old male patient with herniation of the small bowel through a defect in the sigmoid mesocolon. This could not be preoperatively diagnosed as ileus due to internal hernia, but a retro spective review of abdominal computed tomography (CT) showed characteristic findings. Internal hernia must be included in the differential diagnosis of patients with symptoms suggestive of intestinal obstruction but without a history of abdominal surgery. The occurrence of an internal hernia involving the sigmoid mesocolon is not common, with only 43 cases reported in Japan. Of these, only 11 had transmesosigmoid hernia.