A sore stomach !

A 21-year-old man presents with a past history of intermittent abdominal pains. For the last year he has suffered with more frequently bouts of abdominal pains and more recently he has started to vomit some 30 minutes after eating. He has been started on lansoprazole for a couple of months with no response. At gastroscopy (photograph) there is a severe gastritis and a tight pylorus requiring dilatation to examine the duodenum (which was unremarkable).

His blood results are as follows: 
Hb 11.2 g/l 
MCV 105 fl 
WCC 11.9 x 109 
Plat 395 x 109 
Basal gastrin 180 pg/ml (<75) 

WHAT IS THE MOST LIKELY DIAGNOSIS?

a) Hp associated gastritis

Doesn't explain all the 'issues' !

b) Zollinger-Ellison syndrome

There is a simple explanation to that elevated gastrin level!

c) Crohn's disease

Well done!

d) Gastric lymphoma

The antrum would do but how do you explain the macrocytosis?

e) Diffuse type gastric cancer

Could look like this but he is a bit young isn't he? !

explanation

Although the patient has a raised gastric level, this can be explained by the lanzoprazole. The macrocytosis is more difficult to explain. An autoimmune gastritis would be expected to be worse in the gastric body than in the antrum. In fact, the only other possibility is that the patient has terminal ileal Crohn's disease, causing malabsorption of B12 as well as a Crohn's gastritis.  This was indeed the case!  Actually, the diagnosis had already been confirmed by antral biopsies before I carried out the dilatation! Wouldn't like to dilate a diffuse type cancer !