Occult bleeding from Meckel's diverticulum.
D006471:Gastrointestinal Hemorrhage / Q000175:diagnosis*; D006801:Humans; D007443:Intussusception / Q000175:diagnosis; D008297:Male; D008467:Meckel Diverticulum / Q000175:diagnosis*; D008875:Middle Aged; D009780:Occult Blood