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Zorluk: Çok zorPathology and Biopsy Interpretation

A 54-year-old man presents to the clinic with a 6-month history of epigastric pain, early satiety, and occasional nausea. He has no history of nonsteroidal anti-inflammatory drug use. Vital signs are within normal limits. Physical examination reveals mild epigastric tenderness but is otherwise unremarkable. Laboratory studies show a hemoglobin of 11.2 g/dL and a mean corpuscular volume of 78 fL. An upper gastrointestinal endoscopy reveals thickened, erythematous gastric folds in the antrum without frank ulceration. Multiple forceps biopsies are obtained. The histopathology report describes a dense, monomorphic infiltrate of small-to-medium-sized atypical lymphocytes in the lamina propria. These cells are seen infiltrating and destroying the adjacent gastric mucosal glands, forming lymphoepithelial lesions.

Immunohistochemical analysis of the lymphocytic infiltrate reveals the following profile:
- CD20: Positive
- CD3: Negative
- CD5: Negative
- CD10: Negative
- Cyclin D1: Negative

A Warthin-Starry silver stain demonstrates sparse, curved bacilli along the surface epithelium.

Based on these histopathologic and immunohistochemical findings, which of the following is the most accurate diagnosis?

  1. Extranodal marginal zone lymphomaCevap
  2. B
    Chronic active gastritis with reactive lymphoid hyperplasia
  3. C
    Mantle cell lymphoma
  4. D
    Follicular lymphoma
  5. E
    Small lymphocytic lymphoma

Cevap

Extranodal marginal zone lymphoma
The correct diagnosis is extranodal marginal zone lymphoma, commonly known as MALToma. The pathology report describes a monomorphic small B-cell infiltrate (CD20+, CD3-) that is actively destroying native gastric glands (lymphoepithelial lesions). In the diagnostic algorithm for small B-cell lymphomas, immunophenotyping is critical: CD5 negativity excludes mantle cell lymphoma and small lymphocytic lymphoma, while CD10 negativity excludes follicular lymphoma. The remaining primary differential is a marginal zone lymphoma. The presence of curved bacilli on Warthin-Starry stain confirms Helicobacter pylori infection, the primary pathogenic driver of gastric MALT lymphomas. Eradication of H. pylori is often the first-line treatment for early-stage disease.

Adım Adım Çözüm

1
Determine the lineage of the cellular infiltrate.
The atypical lymphocytes are positive for CD20 and negative for CD3, identifying them as a B-cell population.
Establishing B-cell versus T-cell origin narrows the differential diagnosis of lymphoid neoplasms.
2
Evaluate the morphological features described in the pathology report.
The infiltrate is monomorphic and forms lymphoepithelial lesions (invading and destroying gastric glands).
Monomorphic infiltrates and lymphoepithelial lesions indicate an invasive, malignant neoplastic process rather than a benign, polymorphic reactive inflammatory response.
3
Analyze the immunohistochemical marker profile to differentiate small B-cell lymphomas.
The cells are negative for CD5, CD10, and Cyclin D1.
CD5 negativity rules out mantle cell lymphoma and small lymphocytic lymphoma. CD10 negativity rules out follicular lymphoma.
4
Synthesize the pathologic findings with the special stain results.
A CD5-negative, CD10-negative small B-cell lymphoma with lymphoepithelial lesions in the stomach, accompanied by Helicobacter pylori (curved bacilli on Warthin-Starry stain), confirms a diagnosis of MALT lymphoma.
Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALToma) is a CD5-/CD10- small B-cell lymphoma strongly associated with chronic H. pylori infection.

Anahtar Kavram

Diagnosis of extranodal marginal zone lymphoma (MALToma) relies on identifying a monomorphic, CD5-negative, CD10-negative small B-cell infiltrate with characteristic lymphoepithelial lesions, often in the setting of Helicobacter pylori infection.
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