Metachronous EBV-positive classical Hodgkin lymphoma following EBV-positive diffuse large B-cell lymphoma: a case report and literature review.

Epstein-Barr virus (EBV) is closely associated with the development of various malignancies, particularly in lymphomas. Diffuse large B-cell lymphoma (DLBCL), as the most common subtype of non-Hodgkin lymphoma, and classical Hodgkin lymphoma (CHL) both originate from B cells, yet they exhibit significant differences in pathological diagnosis and clinical management. While composite lymphoma (CL) with sequential or simultaneous DLBCL and CHL has been reported, cases where both components are EBV-positive remain rare. Here we report a rare case of composite lymphoma with EBV-positive DLBCL followed by EBV-positive CHL. The patient was a 35-year-old male diagnosed with EBV-positive DLBCL in 2019. After one cycle of CHOP regimen followed by seven cycles of DA-EPOCH-R regimen, he achieved clinical complete remission. Sixty-nine months later, the patient was readmitted due to multiple lymphadenopathy, and the pathological diagnosis was EBV-positive CHL (mixed cellularity type). After two cycles of ABVD chemotherapy, he achieved partial remission, but later showed disease progression and is still under treatment. We discuss this rare case in conjunction with literature review, aiming to provide reference for the diagnosis and treatment of similar cases.