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Difficulty: MediumPathology and Biopsy Interpretation

A 62-year-old woman is evaluated in the clinic for progressively worsening fatigue and mild cognitive decline over the past six months. Laboratory studies reveal a macrocytic anemia and a low serum vitamin B12 level. Upper gastrointestinal endoscopy reveals severe thinning of the mucosa in the gastric body and fundus, with normal-appearing mucosa in the antrum. Multiple biopsies are obtained from the stomach. The pathology report from the gastric body describes severe loss of oxyntic glands, replacement of the native gastric epithelium with goblet cells, a dense infiltrate of lymphocytes and plasma cells in the lamina propria, and nodular hyperplasia of enterochromaffin-like (ECL) cells. Biopsies from the antrum show no significant pathologic changes, and immunohistochemical stains for organisms are negative. Which of the following is the most likely diagnosis based on these histopathologic findings?

  1. Autoimmune metaplastic atrophic gastritisAnswer
  2. B
    Helicobacter pylori-associated gastritis
  3. C
    Reactive chemical gastropathy
  4. D
    Menetrier disease
  5. E
    Gastric marginal zone lymphoma

Answer

Autoimmune metaplastic atrophic gastritis
The correct answer is autoimmune metaplastic atrophic gastritis. The biopsy demonstrates the classic histologic pattern of this condition: oxyntic (parietal) gland destruction, intestinal metaplasia (replacement of native epithelium by goblet cells), and enterochromaffin-like (ECL) cell hyperplasia. The chronic inflammation is notably confined to the gastric body and fundus, while the antrum is spared. The destruction of parietal cells leads to a loss of intrinsic factor, causing the patient's vitamin B12 deficiency and macrocytic anemia (pernicious anemia). The resulting achlorhydria triggers G-cell hyperplasia in the antrum, leading to hypergastrinemia, which subsequently drives the ECL cell hyperplasia seen in the body and fundus biopsies.

Step-by-Step Solution

1
Analyze the patient's clinical presentation.
The patient is an older adult presenting with a macrocytic anemia and vitamin B12 deficiency (pernicious anemia), alongside endoscopic evidence of proximal gastric mucosal thinning.
Establishing the clinical context is essential before interpreting the biopsy results.
2
Interpret the histopathologic findings from the gastric body and fundus.
The biopsy shows loss of parietal (oxyntic) cells, intestinal metaplasia (goblet cells), chronic lymphoplasmacytic inflammation, and ECL cell hyperplasia.
These specific microscopic features define the nature of the mucosal injury.
3
Note the distribution of the disease and negative findings.
The antrum is completely spared, and special stains for infectious organisms are negative.
The anatomic distribution is a key differentiator in forms of gastritis.
4
Synthesize the clinical and pathologic data to formulate a diagnosis.
The constellation of corpus-restricted atrophy, intestinal metaplasia, and ECL hyperplasia in the setting of B12 deficiency confirms a specific autoimmune etiology.
Matching the histological pattern to the disease mechanism establishes the definitive diagnosis.

Key Concept

Autoimmune metaplastic atrophic gastritis is characterized by T-cell-mediated destruction of parietal cells restricted to the gastric body and fundus, leading to oxyntic atrophy, achlorhydria, and secondary enterochromaffin-like (ECL) cell hyperplasia due to hypergastrinemia.
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Topics

Pathology and Biopsy Interpretation

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