BackgroundAdenocarcinoma in an inverted Meckel's diverticulum with intussusception has not been reported to date. We discuss the clinical issues concerning this rare condition and review the relevant literature.Case presentationA 71-year-old Japanese female was referred to our hospital for further investigation of severe anemia. Computed tomography revealed a tumorous lesion in the terminal ileum. Capsule endoscopy did not provide detailed images. Exploratory laparoscopy revealed intussusception in the terminal ileum. An intraluminal tumor 70 cm proximal to the ileocecal valve was observed to be the lead point. Partial resection including the tumor was performed. Macroscopically, a polypoid tumor at the tip of an inverted diverticulum-like structure was observed. The tumor was histologically composed of adenocarcinoma accompanied by gastric and pyloric gland metaplasia in the background mucosa, which was confirmed by immunohistochemical staining. Based on these characteristics, this tumor is considered to have developed from the ectopic gastric mucosa in a Meckel's diverticulum.ConclusionsWhen we encounter patients with unfamiliar lesions in the small bowel, we need to differentiate Meckel's diverticulum related disease. Meckel's diverticulum can invert into the lumen of the small bowel and cause an intussusception, and has potential of malignant transformation.