Clinicopathological analysis of gastric mucosa-associated lymphoid tissue lymphoma

Abstract

Objective To analyze the clinicopathological characteristics, immunophenotypes and immu-noglobulin heavy chain gene rearrangement of gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Methods The clinical data of 35 patients with gastric MALT lymphoma who had been admitted to Southwest Hospital from January 1984 to June 2003 were retrospectively analyzed. The specimens of the gastric MALT lymphoma were obtained and their pathomorphological classifications were studied. The immunophenotypes and immunoglobulin heavy chain gene rearrangement were detected by immunohistochemistry and polymerase chain reaction, respectively. All the data were analyzed by chi-square test and Mann-Whitney U test. Results The main manifestations of patients with gastric MALT lymphoma were epigastric discomfort and abdominalgia. The percentage of patients with age≥40 accounted for 74% (26/35). The gastric MALT lyrnphoma has low differentia-tion in 32 patients, and high differentiation in 3 patients. There were 31 patients in Ⅰ E stage, 2 in Ⅱ E1 stage and 2 in Ⅳ stage. Pathological examination showed that gastric MALT lymphoma was composed of centrocyte-like cells and mononuclear-like B cells or lymphoplasma cells. Twenty-nine specimens were with lymphoepithelial lesions (83%), 2 with follicular colonization (6%), and 11 with plasma cells segregated beneath the surface epithelium (33%). All the 35 specimens were B cell immunotype. Restrictive expression of κ and λ light chains of the immunoglobulin was found in 19 cases, and Bcl-2 positive expression was found in 16 cases. High expres-sion of proliferating cell nuclear antigen was found in gastric MALT lymphoma with transformed blasts, which indicated that gastric MALT lymphoma with transformed blasts was more active in proliferation than those of low grade. A monoclonal pattern of immunoglobulin heavy chain gene rearrangement was detected in 33 patients (94%). Conclusions Digestive symptoms are the main manifestations of patients with gastric MALT lymphoma. The incidence of gastric MALT lymphoma increases with age. The final diagnosis of gastric MALT lymphoma depends on the pathological, immunohistochemical examination and laboratory test. Key words: Lymphoma; Mucosa-associated lymphoid tissue; Pathology; Immune phenotype