BACKGROUND: Internal hernias, a rare type of herniation, occur through deficits of peritoneum or mesentery/mesocolon. Herniation of the small intestine into the mesosigmoid fossa is an extraordinary situation. A possible diagnostic delay may lead to intestinal ischemia, perforation, or even necrosis.

CASE REPORT: A 47-year-old woman was admitted in our Emergency Department with a 24-hour colic pain that started at the epigastrium and then moved to the left pelvic region. Small-bowel obstruction due to internal herniation was diagnosed based on clinical, radiological, and laboratory examination results. We encountered a loop of jejunum that was herniated into the mesosigmoid fossa, making this a unique case, as in most such cases the internal herniated loops are loops of ileum.

CONCLUSIONS: The key role of computed tomography (CT) is highlighted and the characteristic sign of “C-shaped cluster” is mentioned in the literature for intersigmoid hernia. Although internal mesosigmoid hernia is rare, it should be always kept in mind when the patient’s digestive tract is affected. Our main purpose here is to highlight this rare entity for our fellow surgeons.

Keywords: Internal hernia, Jejunum, Mesocolon