Diffuse large B-cell lymphoma with a high number of epithelioid histiocytes (lymphoepithelioid B-cell lymphoma): a study of Osaka Lymphoma Study Group.

The aim of this study was to clarify whether diffuse large B-cell lymphoma (DLBCL) with a high number of epithelioid histiocytes (DLBCL-EH) could have distinctive clinicopathological characteristics. Clinicopathological findings in 22 cases with DLBCL-EH and, as a control, 96 cases with ordinary type of DLBCL were analyzed. There were ten men and 12 women with ages ranging from 38 to 91 (median, 64) years. The primary site was lymph node in 16 cases, extranodal organs in three, and unknown in three. Stage of disease was I in five cases, II in three, III in nine, and IV in five. Histologically, there was a diffuse proliferation of large lymphoid cells admixed with numerous clusters of epithelioid histiocytes sprinkling throughout the lesions. Immunohistochemically, the large lymphoid cells were CD20(+), CD15(-), and CD3(-) and positive for CD10, bcl-6, and MUM1 in nine (41%), eight (36%), and 12 (55%) of 22 cases, respectively. Epstein-Barr virus positive rate was higher in DLBCL-EH (23.8%) than that in ordinary DLBCL (4.5%; P<0.05). Clonality analysis revealed monoclonal bands in all of the examined 20 cases with DLBCL-EH. Multivariate analysis revealed the prominent epithelioid reaction to be an independent factor for favorable prognosis. These findings suggest that DLBCL-EH could be a specific morphological variant of DLBCL associated with a better prognosis.