CD19 and follicular lymphoma: DLBCL, follicular lymphoma, T-cell lymphoma, and mucosa-associated lymphoid tissue lymphoma are commonly seen types of PHL, with DLBCL and mucosa-associated lymphoid tissue being the most frequently reported ones.[24] Macroscopically, PHL is often observed as irregularly bordered, firm masses measuring 2-9cm, with a fish-like appearance on cross-section and occasional focal necrosis.[25] The tumor cells in DLBCL typically exhibit diffuse enlargement and varied lymphoid morphology, expressing B-cell markers CD19, CD20, CD22, PAX5, and CD79a.