An unusal looking gastric polyp

This patient is undergoing a gastroscopy because of dyspepsia. 
WHAT IS THE LIKELY DIAGNOSIS?

a) Hyperplastic polyp

It's unusual to see a ulceration on a hyperplastic polyp

b) GIST

Unlikely as the lesion isn't covered with entirely normal looking gastric mucosa

c) NET

Although there are none of the classical chunky vessels around its neck, there are other smaller nearby lesions with some unusually large vessels

d) Adenoma

Gastric adenomas are usually flat, plaque-like lesions

e) Early gastric cancer (EGC)

EGC is a good guess and patients with atrophic gastritis often do have nearby small type I gastric NET's. However, this isn't an EGC.

explanation

​As you well know, gastric NET's are classified as; type I (70%-80% of gastric NET's) linked with hypergastrinaemia secondary to an atrophic gastritis and classically appearing as multiple, small gastric nodules.  

Then we have the rare type II gastric NET which account for about 5-8% is associated with hypergastrinaemia from a gastrin-secreting tumour such as in the MEN-1 syndrome or the Zollinger–Ellison syndrome.  This was a type II gastric NET which has arisen in a patient with a pancreatic gastrinoma and MEN.  Several other much smaller NET's have arisen in the nearby gastric mucosa.   

Finally, we have the type III NET (20%) which are solitary, large nodules with a high mitotic index arising in a healthy gastric mucosa.  These are the ones not to miss as they need a cancer-like gastric resection.  

To remind you of the lessons from Prof Mark Pritchard's Podcast on gastric NET's, you should;  

AT ENDOSCOPY:
• Look for atrophic gastritis 
• Consider using some pH indicator strips to measure the gastric pH (unless pt is taking PPI)
• Identify all the NETs, record their size and number and sample them for histology and grading
• Take antral and corpus biopsies and ask pathologist to do report on the presence/absence of gastric atrophy and intestinal metaplasia and also ask them to carry out immunohistochemistry stains for ‘gastrin’ in the antral biopsies and ‘chromogranin’ and ‘synaptophysin’ in the gastric body samples.
• Look into the second part of the duodenum for the small submucosal gastrinomas which occasionally are seen in MEN-I
• Consider samples for Coeliac disease if the patient has IDA

CONSIDER OFFERING ENDOSCOPIC RESECTION FOR:
• type I gastric NETs   if >10-15mm
• type II gastric NET   if they’re causing problems (eg bleeding) and/or gastrinoma can’t be resected
• type III gastric NET <1cm (provided that it's no worse grade 1/low grade 2 !)

HISTOLOGY:
If that proliferative index comes back surprisingly high (>10%), make sure that the pathologist hasn't inadvertently counted Ki67 positive cells in the nearby gastric mucosa. Atrophic gastric mucosa is usually more proliferative than the NETs! 

BLOOD TESTS:
• FBC
• Full haematinic screen including B12 and Ferritin of course
• TFTs
• Anti-parietal cell AB & Intrinsic factor AB titres
• Serum gastrin level
• Chromogranin level
• Calcium and PTH level (particularly if MEN1 is suspected)

REQUEST THE FOLLOWING SCANS FOR EVERYONE WITH LIKELY TYPE II AND III DISEASE:
• CT
• 68Gallium DOTA-peptide PET/CT scan
• EUS to search for duodenal wall gastrinomas and small gastrinomas within the pancreas which CT can't see and to search for lymphadenopathy close to the NET