RESUMO
The gastrointestinal tract including oral cavity is the most common location of extranodal lymphomas. In this retrospective study, the histomorphological, immunohistochemical and clinical features of 21 Macedonian cases with diagnosed malignant lymphomas were investigated. The series included 15 males and 6 females, mean age 44 (4-78) years. The most common locations were hard palate (n = 7), gastric site (n = 5), small intestinal wall (n = 2), large intestinal wall (n = 5), and lingual root (n = 2). All cases were B cell lymphomas, 23.8% of them low grade B cell lymphoma of mucosa associated lymphoid tissue, 4.7% mantle cell lymphoma, 47.6% diffuse large cell lymphoma, and 23.8% Burkitt type lymphoma. There was no T cell lymphoma. Most of the cases were positive for CD20 and CD79a. Monoclonality was confirmed by light chain restriction, except for nine cases where it failed due to poor tissue preservation. The fact that eight cases were in the clinically advanced third and fourth stage implied a conclusion that not only primary non-Hodgkin's lymphomas but also secondary lesions could invade the gastrointestinal tract. Immunohistochemical staining was helpful in differentiation between benign and malignant infiltration in low grade lymphomas, and in distinguishing diffuse large cell lymphomas from undifferentiated epithelial neoplasms.