Prevalence of lymphoma subtypes in Shanxi according to latest WHO classification

Abstract

To analyze the prevalence of lymphoma subtypes in Shanxi according to the latest World Health Organization (WHO) classification, and to compare the figures with those in other parts of the world. The hematoxylin and eosin-stained sections of 447 lymphoma cases from the archive files of Shanxi Tumor Hospital were reviewed. Immunohistochemical study was performed using a panel of antibodies, including ALK1, bcl-6, CD (1a, 3, 4, 5, 7, 8, 10, 15, 20, 23, 30, 43, 56, 68, 79a and 99), cyclin D1, EMA, IgD, kappa, lambda, LMP1, PAX5, TdT and Vs38C. In addition, in-situ hybridization for Epstein-Barr virus-encoded RNA (EBER) was carried out. All cases were then reclassified according to the latest WHO classification of lymphoma. Of the 447 cases studied, 385 cases (86.1%) were confirmed to be non-Hodgkin lymphoma (NHL), while 62 cases (13.9%) belonged to classic Hodgkin lymphoma (HL). Of the NHL cases, 68.3% were of B-cell lineage and 30.6% were of T and/or NK-cell lineage. Histiocytic neoplasm accounted for only 0.8% (3 cases). As for the subtyping of NHL, diffuse large B-cell lymphoma was commonest (35.1%), followed by peripheral T-cell lymphoma, NOS (12.0%), extranodal marginal zone B-cell lymphoma (MALT lymphoma) (11.7%), follicular lymphoma (8.6%), T-lymphoblastic lymphoma (7.0%), anaplastic large cell lymphoma (4.2%), B-small lymphocytic lymphoma (3.6%) and mantle cell lymphoma (2.6%). Amongst the 263 cases of B-cell lymphoma, 105 cases (39.9%) expressed immunoglobulin light chain (kappa in 52 cases and lambda in 53 cases) in paraffin sections. Regarding markers for EB virus infection, 14 cases of the B-cell lymphoma gave positive findings with both EBER in-situ hybridization and LMP-1 immunohistochemistry, while 6 of the T/NK-cell lymphoma expressed LMP-1 and 19 showed positive signals for EBER. In NHL, there was discordance in EBER in-situ hybridization and LMP-1 immunohistochemical results. As for HL, EB virus positivity was noted in 37 of the 62 cases (59.7%), including 7 cases of lymphocyte-rich HL, 11 cases of mixed cellularity HL and 19 cases of nodular sclerosis HL. In classic HL, there was complete concordance of results by both EBER in-situ hybridization and LMP-1 immunohistochemistry. The prevalence of diffuse large B-cell lymphoma in Shanxi is similar to that in America, Australia, Japan and Korea. The incidence of follicular lymphoma however is much lower than America and Australia.