Nasopharyngeal and sinonasal malignant lymphoma (Histopathologic and immunophenotypic evaluation of 28 cases)

Abstract

In Western countries, non-Hodgkin lymphomas (NHL) presenting in nasopharyngeal and especially in sinonasal region are very rare. In contrast, in Asian countries sinonasal region is the second frequent involvement site of extranodal lymphomas following gastrointestinal lymphomas. In this study, incidence, histologic types and immunophenotypes of nasopharyngeal and sinonasal lymphomas were reviewed. Twenty-eight NHL cases including 16 nasopharyngeal and 12 sinonasal lymphomas were extracted from a total of 340 extranodal NHLs in the archives of Pathology Department, Ege University Faculty of Medicine between 1985 and 1995. Each case was classified according to "Working Formulation" and 25 cases with available paraffin embedded specimens were studied immunohistochemically with LCA, L-26, UCHL-1, CD-43 and CD-30 in order to label immunophenotypes. In our ten-year archival material, of 340 extranodal non-Hodgkin lymphomas nasopharyngeal and sinonasal lymphomas were 4.7 % and 3.5 %, respectively. The most frequent histologic type was diffuse large cell type, accounting half of the cases and most presenting in the nasopharynx (79%). The second most frequent histologic type was mixed small and large cell type (35.7%), majority arising from the sinonasal region (80%). Nasopharyngeal lymphomas expressed predominantly B-cell phenotype (69.2%) and sinonasal lymphomas showed predominantly T-cell phenotype (66.6%). The ratio of T to B phenotype was 2:1 and 1:2.2, for sinonasal lymphoma and nasopharyngeal cases, respectively. Five of eight sinonasal T-cell lymphomas were angiocentric T-cell lymphoma. In conclusion; when the incidence and immunophenotypic values of our cases with sinonasal and nasopharyngeal lymphomas were compared with other countries, they were found to be more close to Asian countries (China and Japan) than Western countries.