CD19 and diffuse large B-cell lymphoma: The DLBCL component consisted of a sheet-like proliferation of large, mononuclear lymphoid cells (Figure 1D) that stained strongly for CD45, PAX5, CD19, CD20 (Figure 1E), and CD79a and exhibited ≥30% reactivity for CD10, BCL6, and MUM1, consistent with a GCB phenotype by Hans algorithm.5 Additional IHC showed that the DLBCL component was positive for MYC but negative for BCL2, CD30, and CD15.