A 15 year old girl presents with intermittent nausea and vomiting for 1 month; this tended to occur approximately 20 to 30 minutes following meals.

Further questioning reveals the presence of continuous dull epigastric pain for 6 months. Her medical and surgical histories are unremarkable.

Her full blood count is significant for a Hb of 9.8 g/dL, with MCV 73 fL, MCH 23 pg, MCHC 31 g/dL. A blood film reveals a hypochromic microcytic anemia, with anisopoikilocytosis.