Indeed, in addition to a predominant polyclonal B‐cell population, flow cytometric analysis (Figure 1G) revealed the presence of two cell populations with different immunophenotypes: a population of high side scatter (SSC), CD19+, CD20+, CD22+, CD15+dim, CD30+dim, CD45+ cells (blue population) and a few CD19‐, CD20‐, CD15+dim, CD30+bright, CD45‐ cells (red population). Findings raised a differential diagnosis between unclassifiable B‐cell lymphoma with characteristics intermediate between DLBCL and classical Hodgkin lymphoma (CHL) versus composite lymphoma (CL) associating DLBCL with CHL. This evidence concerns the gene FUT4 and Hodgkins lymphoma.