The trouble with investigating anaemia in young adults: bleeding from a giant Meckel's diverticulum without ectopic gastric mucosa.

Giant Meckel's diverticulum is rare and usually presents in childhood with haemorrhage or bowel obstruction. Bleeding results from the presence of ectopic gastric mucosa causing peptic ulceration of adjacent mucosa. We discuss the case of a 21-year-old man with a giant Meckel's diverticulum who presented with rectal bleeding. A Meckel's scan was negative and histology following surgical excision ruled out the presence of ectopic gastric mucosa. There was however evidence of chronic inflammation and small bowel mucosal ulceration. We hypothesize that this arose from ischaemia and pressure necrosis because of the large size of the diverticulum and chronic distension by food debris. This case highlights the difficulties in investigating anaemia in young adults despite modern imaging techniques.