**5. Conclusion**

MALT gastric lymphoma is a variant of MZL with an indolent prognosis and long survival, but a high tendency to develop relapses over time.

Diagnosis and differential diagnosis of lymphoma is difficult and includes morphological and immunohistochemical analysis. In this study, morphoimmunological criteria for the diagnosis of MALT gastric lymphoma and differential diagnosis with processes similar in histological picture (reactive infiltrates, peripheral small-cell B-cell lymphomas of the stomach) were developed.

Most informative morphological combinations were selected to differentiate MALT-lymphoma from neoplasias with a similar morphological pattern or reactive lymphoid infiltration. Tumor cell size was considered the most important morphological criterion in tumor tissue analysis: the larger the tumor cells, the greater the changes in their cytomorphological appearance involving nuclear shape, chromatin status and increased cytological atypia.

Potential value of frozen and paraffin section immunohistochemistry was assessed in the common and differential diagnoses of MALT-lymphoma. The immunological diagnosis must be made basing on changes in immunoarchitecture if other immunological criteria are absent.

The consistent application of different treatment methods is the key to the success in treating this category of patients. Conservative anti-*Helicobacter pylori* therapy in the early stages in primary patients gives good results and is a strategy necessary to maintain adequate organ function and prevent the toxic effects of chemotherapy, which, in turn, is used in the progressive refractory course of the disease. New drugs and targeted agents open up the possibility of treating people with severe pre-treatment (inadequate therapy in the early stages of the disease), as well as in certain categories of elderly patients with severe comorbidity.
