[Gastric MALT-type lymphoma. Pathology, pathogenesis, diagnostics and therapy].

Helicobacter pylori infection plays a central role in the development of gastric MALT-type (mucosa-associated lymphoid tissue) lymphoma. Infection results in chronic H. pylori gastritis and stimulates together with antigens or autoantigens proliferation of B-lymphocytes which is the basis for the neoplastic transformation. Histology of MALT-type lymphoma is architecturally similar to the physiological MALT. Invasion and destruction of the gastric epithelium with development of so-called lympho-epithelial lesions is the most important diagnostic criterion. Cytologically MALT-lymphoma resembles centrocytes and monocytes. For definitive lymphoma diagnosis and for the differential diagnosis from other small cell lymphomas in the stomach immunohistochemistry can be helpful. The phenotype of MALT-type lymphoma is identical to non-neoplastic B-lymphocytes of the marginal zone (CD20+, CD5-, CD10- and CD23-). Individual therapy is strongly dependent from histological type and lymphoma stadium. Therapy modalities are H. pylori eradication, radiochemotherapy, surgery or a combination of these. Aim of the therapy is the complete lymphoma regression and cure of the disease.