The prevalence of MYD88 mutation in primary DLBCL of the CNS or testis was significantly higher than previously reported studies in the whole DLBCL series ranging from 6.5% to 19.3% but similar to the observation in ABC-DLBCL (39%) [13, 18, 25–27]. The gene discussed is MYD88; the disease is diffuse large B-cell lymphoma.