Inverted Meckel's Diverticulum: A Rare Cause of Intussusception.

Meckel's diverticulum (MD) is the most common congenital anomaly of the gastrointestinal tract. Rarely, MD has been noted to invaginate, which causes a pathological lead point for intussusception and causes small bowel obstruction. Diagnosing inverted Meckel's diverticulum (IMD) can be difficult due to its rarity, vague presentation, and limitations of conventional imaging modalities in picking it up. A 56-year-old woman was referred to the Gastroenterology clinic after a recent hospital admission for infectious gastroenteritis. She reported being generally well with few symptoms. She had a tendency to constipate, opening her bowels only once in every 5-6 days. Computed tomography of the abdomen and pelvis with contrast showed a 4 cm mid small bowel polyp with an 8 cm stalk, thought to be a lipoma. Oral route double balloon enteroscopy failed as the polyp was not accessible due to its location. She underwent elective laparoscopy, which showed an intussuscepting polyp at the proximal ileum, and wedge resection of the proximal ileum was performed with an intestinal stapler with side-to-side anastomosis. Histology showed MD, which inverted into the small bowel lumen. This case highlights the need to consider IMD in the differential diagnosis of unexplained gastrointestinal symptoms, particularly in middle-aged and older adults. Increased awareness of this rare entity can facilitate early recognition and timely intervention, ultimately improving patient outcomes.