A 41-yr-old woman presented with fever and lymphadenopathy.Positron emission tomog.-computed tomog. (PET/CT) showed disseminated lymphadenopathy, osseous deposits, and a left retroperitoneal mass.Right axillary lymph node biopsy showed mixed cellularity classical Hodgkin lymphoma (cHL), and marrow biopsy confirmed lymphoma infiltration.She was treated with ABVD (adriamycin, bleomycin, vinblastine, dacarbacine), but developed high fever and hypotension after the first dose of bleomycin.Subsequently, bleomycin was replaced by the anti-CD30 antibody conjugate brentuximab vedotin (BV) (1.2 mg/kg) (AAVD).PET/CT after 2 cycles of AAVD showed resolution of all lesions except for the retroperitoneal mass, and the mass did not resolve on PET/CT after the fourth cycle of AAVD and was biopsied, showing paraganglioma.Twelve months after the last dose of BV, she presented with disseminated lymphadenopathy, and PET/CT showed cervical, supraclavicular, axillary, and mesenteric lymphadenopathy.Next-generation sequencing of 35 lymphoid-relevant genes (ALK, ATM, BCL10, BCL2, BCL6, BIRC3, BTK, CARD11, CD79A, CD79B, CRKL, DNMT3A, EZH2, FBXW7, IDH1, IDH2, IRF4, JAK1, JAK2, JAK3, MALT1, MTOR, MYC, MYD88, NOTCH1, POT1, RHOA, SETD2, SF3B1, STAT3, STAT5A, STAT5B, TET2, TP53, and XPO1) was performed (Illumina MiSeq, Illumina, San Diego, CA, USA).PML developed after a median of 3 (2-6) doses of BV, and 7 (3-34) weeks post-BV treatment.EBV + DLBCL was diagnosed 12 mo after the last dose of BV, which appeared longer than that in BV-associated PML.Side-effect profiles of AAVD appeared favorable, but the number of patients treated was small.Observations in more patients will be needed in order to define if the putative immunosuppressive effects of BV might lead to other short-term and long-term adverse events.