Immunohistochemical study revealed diffuse strong expression of CD 10 and CD 20 in tumor cells, Ki-67- over 90% proliferative activity; MUM1: negative reaction; BCL-6: positive nuclear expression in about 70% of the neoplastic population; CD3,CD5: positive stromal T cells; CD23: membrane expression in small groups of cells at the invasion front; Cyclin D1: lack of expression in tumor cells under positive internal control. The gene discussed is BCL6; the disease is neoplasm.