Inverted Meckel’s diverticulum in adults: two case reports and a systematic review

Inverted Meckel’s diverticulum (IMD) is a rare condition that may present as adult intussusception or as an intraluminal small-bowel lesion. Because its clinical and radiological features are nonspecific, IMD is frequently misdiagnosed preoperatively as a small-bowel tumor or another lead-point lesion. This study aimed to clarify the clinical spectrum, diagnostic features, and management of adult IMD. We conducted a systematic review of published adult cases of pathologically confirmed IMD reported between January 2006 and December 2025. PubMed and Web of Science were searched using predefined terms. Eligible studies were case reports or case series involving adult patients aged 18 years or older. Pediatric cases, non-IMD cases, conference abstracts, editorials, review articles without original patient-level data, and non-English publications were excluded. Two institutional cases are presented separately and were not included in the pooled review dataset. Sixty-eight reports describing 69 adult patients met the inclusion criteria. Adult IMD showed heterogeneous and nonspecific clinical presentations, most commonly abdominal pain, gastrointestinal bleeding, vomiting, anemia, or bowel obstruction. Computed tomography (CT) was the most frequently used diagnostic modality and often demonstrated intussusception, a polypoid intraluminal mass, a fat-attenuation core, or a surrounding soft-tissue collar in the distal ileum. Nevertheless, preoperative diagnosis remained difficult, and several lesions were initially suspected to be lipomas or neoplasms. Small-bowel capsule endoscopy and device-assisted enteroscopy helped identify bleeding or ulceration and localize the lesion before surgery in selected clinically stable patients. Surgical resection was performed in most reported cases, and postoperative outcomes were generally favorable. The two institutional cases further illustrate the variable presentation of adult IMD and the complementary diagnostic value of CT, capsule endoscopy, and device-assisted enteroscopy. Adult IMD is a rare but clinically important cause of intraluminal ileal lesions and adult intussusception. Recognition of characteristic CT findings, together with selective use of small-bowel endoscopy in clinically stable patients, may improve preoperative suspicion and support surgical planning. Surgical resection remains central to definitive diagnosis and treatment.