A B-cell non-Hodgkin lymphoma (NHL) that typically affects elderly patients in the 7th and 8th decades.

Epidemiology

• Peak incidence: 7th and 8th decades
  

Etiology

• Gastric MALTomas: multiple studies show an association with H. pylori infection.
  • The prevalence of H. pylori infection in low-grade gastric MALTomas is up to 90%.
• Nongastric MALTomas: frequent association with autoimmune conditions
  • Salivary gland MALTomas: see Sjogren syndrome

Pathophysiology

The most common trigger for gastric MALT lymphoma is Helicobacter pylori infection, which leads to local recruitment and proliferation of antigen-specific T and B lymphocytes. Over time, chronic immune stimulation results in the emergence of a monoclonal B-cell line that proliferates excessively in the presence of H pylori antigens. This cell line eventually accumulates genetic abnormalities that allow it to proliferate in an antigen-independent fashion, resulting in spread away from the local site of infection.

Clinical features

• Gastric MALTomas
  • Present similarly to peptic ulcer disease and gastritis
  • Abdominal pain
  • Melena, hematemesis, potentially anemia
  • Fatigue, weight loss
• Non-gastric MALTomas
  • Salivary MALToma: parotid enlargement

Diagnostics

• Histopathology and immunohistochemistry
  • Thick infiltrates of small to medium-sized lymphoid cells
  • Granulation tissue, ulcerations
  • Immunologic phenotyping: markers of B-cell lymphoma (e.g., CD20)
• Endoscopy

Treatment