A group of 32 patients with malignant gastric lymphomas was subjected, after a 10-year period, to clinical, histological and immunohistological examination. The material comprised small endoscopic specimens as well as larger excisions or resected portions of the stomach. In twelve patients the authors found highly malignant ML. In twenty patients a tumour with a low malignancy was involved. In the group primary and secondary ML were found. In 18.7 % of patients a secondary ML was involved, in the remainder a primary gastric ML. In lymphomas with a low malignancy the tumour population was in the majority monomorphous formed by CCL (centrocyte-like cells), by monocytoid B cells or cells which look-like small lymphocytes with mild irregularity of the nuclei. Lymphoepithelial lesions were detected in these cases in 45 %. In highly malignant lymphomas lymphoepithelial lesions were found in one patient. The majority of tumours were B type CD20+. In one case a peripheral T cell lymphoma with CD45RO+ cells was found. In two cases mantle cell lymphomas were revealed. Both primary and secondary mantle cell lymphomas were involved. They had a common immunophenotype: CD5+, CD20+, CD23–, cycline D1+. The secondary mantle cell lymphoma was CD10+. Positivity of Bcl-2 oncoprotein was found in six cases. In one case (anaplastic large cell lymphoma CD30 positive), the tumour originated from lymph node and infiltrated the stomach secondary. The second seconda- ry malignant lymphoma Bcl-2 positive was mantle cell lymphoma. In the remaining four cases Bcl-2 oncopro- tein positive primary gastric lymphomas were found. The antibody against Bcl-2 oncoprotein is an important factor in assessment of apoptosis.

        Key words: stomach – malignant lymphomas – histological examination –immunohistology