title: Classification of primary gastric lymphomas according to histologic features.
abstract: Histologic features of low-grade gastric lymphomas of mucosa-associated lymphoid tissue (MALT) have been extensively described, and transformation to a large cell (high-grade) lymphoma can occur. We characterize high-grade gastric lymphoma histologically in an attempt to distinguish between MALT-type and non-MALT-type lesions. We studied a series of 60 gastric lymphomas and characterized them clinically, histopathologically, and immunophenotypically. Low-grade gastric lymphomas were classified according to established criteria. High-grade lymphomas were classified in three groups based on the presence or absence of a low-grade component and lymphoepithelial lesions (LELs): 1) high-grade MALT lymphomas appearing in low-grade MALT lymphomas (LG/HG MALT lymphoma); 2) large cell lymphoma with LELs composed of large cells (high-grade LELs) but without a low-grade component (HG MALT lymphoma); and 3) diffuse large cell lymphoma without a low-grade MALT lymphoma component or LELs (DLCL). Twenty-two lymphomas were classified as low-grade MALT lymphomas, 16 as LG/HG MALT lymphomas, 10 as HG MALT lymphomas, and 12 as DLCL. B-cell immunophenotype was confirmed in all 55 cases in which immunophenotyping was performed. Low-grade LELs were seen in all low-grade MALT lymphomas, and CD20(L26) expression confirmed B-cell phenotype in the LELs in 20 of 20 cases. Clinical follow-up was available for 56 patients (range, 1-264 months; mean, 57 months). Actuarial analysis of disease-specific survival and relapse-free survival showed that clinical stage was highly statistically significant (P < 0.0001), whereas histologic type and grade approached statistical significance. Multivariate analysis showed that clinical stage was the only significant factor in relapse-free and disease-specific survival.
authors.affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor, USA.
authors.forename: E D
authors.initials: ED
authors.lastname: Hsi
authors.forename: A
authors.initials: A
authors.lastname: Eisbruch
authors.forename: J K
authors.initials: JK
authors.lastname: Greenson
authors.forename: T P
authors.initials: TP
authors.lastname: Singleton
authors.forename: C W
authors.initials: CW
authors.lastname: Ross
authors.forename: B
authors.initials: B
authors.lastname: Schnitzer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000378:metabolism; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D018442:Lymphoma, B-Cell, Marginal Zone / Q000145:classification / Q000378:metabolism / Q000473:pathology*; D008228:Lymphoma, Non-Hodgkin / Q000145:classification / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D016612:Paraffin Embedding; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000145:classification / Q000378:metabolism / Q000473:pathology*
chemical_list: D015703:Antigens, CD