Clinicopathologic Study of Primary Gastric Lymphoma of B-cell Lymphoma of MALT

Song, In Sung; Choi, Kyoo Wan; Kim, Chung Yong; Kim, Chul Woo; Jung, Hyun Chae; Lee, Kyung Mee; Chin, Young Joo; Chang, Dong Kyung; Jung, Woon Tae

Abstract

Background/Airns: Most of the primary gastric lymphoma (PGL) are derived from mucosa- associated lymphoid tissue (MALT) and thus, differ from nodal lymphoma in both histologic features and biologic behavior. Recent studies showed that H, pylori infection was closely related to the development of low grade gastric lymphoma, and eradication of the infection could induce regression of the tumor. The aim of this study was to elucidate the clinicopathological behavior of PGL according to the concept of MALT.
METHODS
Fifty one cases of PGL of B-cell phenotype in stages IE and IIE, were examined retrospectively. The histologic classification of MALT-derived lymphoma was applied. Depth of invasion and regional lymph node involvement were evaluated with surgical specimen and K. pylori infection was defined on endoscopic biopsy specimens.
RESULTS
Mean age was 49.6 yrs and M/F ratio was 1.43 to 1. Histologically, low grade (n=26, 51%) could be distinguished from high grade with (n=11, 22%) and without (n=14, 27%) evidence of a low grade component. The H. pylori infection rate was higher in low grade (81%) than in high grade (27%). The endoscopic findings of low grade group were usually superficial multiple erosions and/or ulcerations (52%), while high grade group predominantly showed ulceroinfiltrative lesions (54%) or masses (25%). In low grade group, 75% were limited to mucosa and submucosa, but regional lymph node involvement was 40%. Twenty nine percent of preoperative stage IE cases were upgraded to stage IIE in postoperative reevaluation.
CONCLUSIONS
Whe:n the H. pylori eradication is employed as a therapeutic modality for patients with H. pylori-positive low grade gastric MALToma, regional lymph node involvement should be thoroughly evaluated.