Autoimmune metaplastic atrophic gastritis

Autoimmune metaplastic atrophic gastritis, also autoimmune gastritis is a rare pathology of the stomach. It is closely associated with pernicious anemia.

General

• Pathology: loss of parietal cells, gastric atrophy, macrocytic anemia.
• Etiology: autoimmune.

Diagnosis based on serology for antibodies to:

• Parietal cells.
• Intrinsic factor.

Others:

• Gastrin level (increased).
  • Normal < 100 pg/mL.

Note:

• Parietal cells produce intrinsic factor (important for vitamin B12 absorption) and hydrogen chloride, i.e. stomach acid.

Gross

• Diffuse erythema.^{[citation needed]}

Microscopic

Features:

• Corpus predominant inflammation - usu. moderate or severe - key feature.
• Loss of parietal cells.
• Increased G cells in the antrum.
  • Produce gastrin to stimulate the (missing) parietal cells.

Notes:

• Compare with other types of gastric atrophy.

DDx:

• Gastric neuroendocrine tumour.

IHC

Features:

• Chromogranin A +ve (demonstrates nodular enterochromaffin-like cell hyperplasia).
• Gastrin -ve (body of stomach).
  • +ve in antrum.

Images:

• Autoimmune gastritis - chromogranin A (nih.gov).
  • Findings may be seen in hypergastrinemia and nodular enterochromaffin cell-like (ECL) hyperplasia.

Sign out

STOMACH, BIOPSY:
- SEVERE CHRONIC ACTIVE GASTRITIS WITH EXTENSIVE INTESTINAL METAPLASIA.
- NEGATIVE FOR HELICOBACTER-LIKE ORGANISMS.
- NEGATIVE FOR DYSPLASIA AND NEGATIVE FOR MALIGNANCY.

COMMENT:
Parietal cells are not apparent on the H&E stained sections. Immunostains show 
rows of Chromogranin A positive cells and a lack of gastrin staining.  

These findings suggest an autoimmune gastritis; correlation with blood work 
is suggested.

See also

• Stomach.
• Gastritis.
  • Chronic gastritis.
• Anemia.