A 29 year old man presented with black stools to the emergency department while in Germany in 2000. He was otherwise asymptomatic at the time, and a gastroscopy and colonoscopy were normal. His bowel habit normalised, so he was discharged and advised to contact his general practitioner when he returned to England. Eight years later, aged 37, he presented to our institution with a similar episode. During this admission his haemoglobin remained normal and a repeat gastroscopy and colonoscopy were normal. He was again discharged. In 2010 he presented again to the surgical department with another episode of black stools. This time, on admission his haemoglobin was noted to be 80 g/L (reference range 130-180). All his other blood test results were normal. He underwent a blood transfusion and a repeat gastroscopy, which was again unremarkable.

A nuclear medicine scan raised the suspicion of the likely diagnosis, which was confirmed at laparoscopy.