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Intermittent abdominal pain and melaena in a 64-year-old man.

A 64-year-old man presented with a four-day history of intermittent abdominal pain and melaena. The patient had no past history of cancer and no family history of colorectal cancer. Physical examination revealed mild periumbilical and right lower quadrant abdominal tenderness without rebound tenderness. Laboratory examination showed no abnormality. Contrast-enhanced computed tomography (CT) (figure 1A, 1B and 1C) showed an intussusception in the right lower quadrant: a segment of bowel accompanying blood vessel density and adipose tissue density within the lumen of caecum (arrows). Colonoscopy (figure 1D and 1E) revealed a sausage-like mass with superficial hyperaemia and mucosal erosion in the ileocaecal valve.