Duodenal intussusception is a rare entity. To date, only a few cases have been reported in the literature. In this report, a case of duodenal intussusception due to an unusual tumor was presented and the clinical features of this entity were discussed. A 42-year-old man with Peutz-Jeghers syndrome presented with epigastric pain, vomiting, and severe anemia. Computed tomography scan revealed synchronous duodenojejunal and jejunojejunal intussusceptions. An emergency laparotomy revealed a polypoid mass originating from the lateral wall of the descending duodenum with intussusception of the distal duodenum. Histological examination demonstrated a poorly differentiated neuroendocrine carcinoma with muscularis infiltration, vascular invasion, and a Ki-67 index of 20%. A comprehensive literature search revealed 44 English reports that provided adequate descriptions of an additional 47 such cases. Clinical presentation was usually chronic and nonspecific. Diagnostic modalities included ultrasonography, upper gastrointestinal series, computed tomography, and endoscopy. Five patients were due to a non-neoplastic lesion; however, the other 43 patients were secondary to a tumor, benign in 35 cases and malignant in eight cases. Only one patient was treated by endoscopic polypectomy, whereas the remaining underwent open surgeries. Duodenal intussusception is a challenging condition due to its rarity and nonspecific presentation. It should be considered in the differential diagnosis of gastric outlet obstruction, upper gastrointestinal bleeding, pancreatitis, and obstructive jaundice.