Autoimmune Atrophic Gastritis

Definition

• Atrophic gastritis accompanied by anti-parietal cell and anti-intrinsic factor antibodies

Alternate / Historical Names

• Autoimmune metaplastic atrophic gastritis
• Type A gastritis

Diagnostic Criteria

• Requires a biopsy from the body for diagnosis
• Atrophic gastritis largely restricted to the gastric body
• Antrum usually normal but may show focal inflammation and atrophy
• During active phase, there is a lymphocytic and plasma cell infiltrate
  • Centered in the deep lamina propria of the body
  • Typically sparse in cases with advanced atrophy
• In chronic phase, there is markedly thinned mucosa composed largely of foveolae
• Atrophy of oxyntic glands
  • Destruction and loss of both parietal and chief cells
  • Usually extensive but need not be complete
  • Results in pseudopyloric metaplasia
• Intestinal metaplasia is usually extensive
• Gastric endocrine cell proliferations frequently associated
  • Occurs in body, not in antrum
  • May begin early in disease
  • (G cell hyperplasia occurs in antrum)
    • (There are no G cells in the body)
• Anti-parietal cell and anti-intrinsic factor antibodies
  • Pernicious anemia may develop in longstanding cases
    • May take years for body stores of vitamin B12 to be depleted
• Low prevalence of Helicobacter

Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342

Original posting : September 9, 2009

Differential Diagnosis

• Helicobacter associated chronic gastritis can result in antral atrophy with or without intestinal metaplasia that is indistinguishable from the atrophic body mucosa of autoimmune gastritis
  • Endocrine cell hyperplasia is not typical of Helicobacter
  • Clinicopathologic correlation with knowledge of the location of the biopsy is necessary for the distinction

Clinical

• Rare
• Frequently results in
• Achlorhydria
• Hypergastrinemia
• Vitamin B12 deficiency
• Iron deficiency
• Loss of pepsin
• Associated with development of intestinal type gastric adenocarcinoma
  • Risk is very low in USA
  • Risk significantly increased only in regions with a high endemic risk of gastric carcinoma

Classification/Lists

Gastritis / Gastropathy

• Reactive gastropathy / chemical gastritis
  • Includes most acute gastritis
  • Various causes including:
    • Alcohol
    • NSAIDS and other drugs
    • Bile and/or duodenal contents (alkaline) reflux
      • Frequently post-surgical
• Chronic gastritis and chronic active gastritis
  • Non-atrophic, predominantly antral
    • Includes Helicobacter-associated chronic active gastritis
    • Late stages may have multi-focal atrophy
  • Atrophic, fundic
    • Autoimmune
• Other drug related gastritis
  • Iron
    • Stainable iron crystalline material present
  • Aluminum based antacids (gastric mucosal calcinosis)
    • Small, pink, partially calcified. refractile crystals
  • Kayexalate
    • Rhomboid or triangular, non-polarizable basophilic crystals
  • Chemotherapy
  • See excellent reviews
    • Parfitt and Driman, Hum Pathol 2007, 38:927
    • Srivastava and Lauwers, Histopathol 2007, 50:15
• Hypertrophic/hyperplastic gastritis
  • Menetrier disease
  • Zollinger Ellison syndrome
• Special types
  • Collagenous
  • Lymphocytic
  • Eosinophilic gastroenteritis
  • Granulomatous
• Vascular
  • Gastric vascular antral ectasia (GAVE)
  • Portal hypertensive gastropathy
  • Ischemic
• Infectious
  • Helicobacter
  • Viral
  • Fungal
  • Parasitic

Bibliography

• Noffsinger A, Fenoglio-Preiser CM, Maru D, Gilinisky N.  Gastrointestinal Diseases, AFIP Atlas of Nontumor Pathology, First Series, Fascicle 5, 2007.
• Owen DA. Gastritis and carditis. Mod Pathol. 2003 Apr;16(4):325-41.
• Srivastava A, Lauwers GY. Pathology of non-infective gastritis.Histopathology. 2007 Jan;50(1):15-29.