We report a case of age-related EBV-associated B-cell lymphoproliferative disorder (age-related EBV+ B-cell LPD) metachronously showing two distinct morphologic appearances: one of a polymorphic disease resembling classical Hodgkin lymphoma (CHL), and the other of a large-cell lymphoma. A 71-year-old man was admitted to the St. Marianna University Hospital because of fever and generalized lymphadenopathy. Right axillary lymph node biopsy revealed mixed cellularity classical Hodgkin lymphoma (MCHL). The patient was referred to the Tokyo Medical Center, where he was treated with chemotherapy and obtained CR. One year later, the patient again developed fever and generalized lymphadenopathy. Biopsy of the right cervical mass revealed a diagnosis of diffuse large B-cell lymphoma. The patient was treated with salvage chemotherapies and obtained the second CR. Two years later, the patient developed acute myeloid leukemia (AML). Although CR was achieved with chemotherapy, AML relapsed 5 months later and proved to be refractory. Two and a half years later, the patient developed right cervical lymph node enlargement. The biopsy again revealed diagnosis of MCHL. The patient died 2 months later. On reviewing all of the biopsy specimens, including the findings of immunohistochemistry and in situ hybridization, possibility of CHL was ruled out, because neoplastic giant cells resembling Hodgkin and Reed-Sternberg (HRS) cells were positive for both Oct2 and BOB.1, which has not been reported in CHL. Both HRS-like cells at the time of diagnosis of Hodgkin lymphoma and lymphoma cells at the time of diagnosis of non-Hodgkin lymphoma were positive for CD20 and EBV-encoded small RNAs. This case was finally diagnosed as having age-related EBV+ B-cell LPD. We report the case here as it underscores the difficulty in diagnosing age-related EBV+ B-cell LPDs and also suggests an important role of EBV in the pathogenesis of lymphoid neoplasms.