MYD88 and primary central nervous system lymphoma: More than 90% of PCNSL cases are of the diffuse large B-cell type [4] and the majority of which have ≥ 1 mutations in the NF-kB and B-cell receptor signaling pathways, such as CD79B, MYD88, TBL1XR1, CARD11, or CDKN2A [5].