Prognostic significance of the histopathologic recognition of low- and high-grade components in stage I-II B-cell gastric lymphomas

Abstract

The prognostic value of histopathologic features was assessed in 83 patients with stage I-II gastric B-cell lymphomas (PGL). The following histotypes were considered: low-grade mucosa-associated lymphoid tissue (MALT)-type lymphoma (LGML; n = 35), diffuse large B-cell lymphoma with areas of MALT-type lymphoma (DLCLML; n = 20) and diffuse large B-cell lymphoma without areas of MALT-type lymphoma (DLCL; n = 28). Low-grade (LG) and high-grade (HG) components, lymphoepithelial lesions (LEL), size of cells giving rise to LEL, and amount and growth pattern of large cells (LC) were analyzed. Five-year cause-specific survival (CSS) for patients with LGML, DLCLML, and DLCL were 94%, 84%, and 64%, respectively (p = 0.05). LG component or LEL were associated with a significantly longer 5-year CSS, whereas the presence of an HG component, defined as clustered LC greater than 10% of neoplastic population, was significantly related to a shorter survival. Lymphomas with LC disposed in clusters were associated with a worse survival in comparison with cases with scattered LC. The presence of scattered LC 5%-10% appeared irrelevant in LGML. When analysis was limited to DLCLML/ DLCL patients, the presence of LG component or LEL was associated with a significantly longer 5-year CSS, whereas the existence of LEL formed by LC (HG LEL) did not modify survival. Multivariate analysis, adjusted by the main prognostic factors, confirmed the independent and significant association between histopathologic categorization and survival. Age, stage, lactate dehydrogenase (LDH) ratio, thrombocytopenia, and use of chemotherapy had independent prognostic value. In conclusion, histopathologic categorization is an independent prognosticator in PGL. The formation of compact clusters by LC, rather than their amount, is a true prognostic variable. The presence of scattered LC 5%-10% appears irrelevant in LGML. LG component and LEL are favorable predictors in HG lymphomas, helping to identify two subsets of DLCL with different prognosis.