PCNSL harbor BCR-activating mutations in CD79B and TLR-activating mutations in MYD88 at a higher frequency than systemic ABC type DLBCL, whereas oncogenic mutations in CARD11 and TNFAIP3 occur less frequently in PCNSL [20,21,22,23,24]. The gene discussed is CD79B; the disease is aneurysmal bone cyst.