The risk of developing Hodgkin lymphoma (HL) is increased in immunodeficiencies or during the treatment of some autoimmune diseases. The development of new therapeutic agents has highlighted the risk of unusual lymphoid proliferations, particularly classical HL (cHL). We report the clinicopathological findings of 13 cHL arising in patients treated for a primary haematological malignancy. Eight patients had received an immunomodulator, protein tyrosine-kinase inhibitor or monoclonal antibody, which may have contributed to the cHL development. Most patients had disseminated disease with poor prognostic factors at cHL diagnosis. Despite the initial presentation, good outcomes were achieved with standard cHL chemotherapy.