A 50-year-old man was admitted to our hospital with abdominal pain and repeated vomiting. He was afebrile and had upper abdominal tenderness. Basic laboratory test results were normal. Abdominal CT showed an enhanced mass lesion, 40 mm in diameter, in the small intestine (A). Retrograde double-balloon endoscopy (DBE) revealed a diffuse thickening of the ileum that involved half of the circumference of the bowel (B). Indigo carmine dye spray enhanced the image to reveal swollen villi of different sizes (C).