BACKGROUND: Sequential Epstein-Barr virus (EBV)–positive B cell lymphoma to the initial diagnosis of angioimmunoblastic T cell lymphoma (AITL) is very rare, the exact mechanism and standard therapy of which is still being explored. CASE: A 50-year-old man was admitted to our hospital in January 2014 with a three-week history of enlargement of multiple lymph nodes. His initial pathological evaluation indicated AILT. The reactivation of EBV was observed during the immunosuppression therapy for AITL, accompanied by onset of subcutaneous nodules proven to be EBV-positive diffuse large B cell lymphoma (DLBCL) based on the pathological findings of rebiopsy. The patient was successfully treated with chidamide, a histone deacetylase (HDAC) inhibitor, and rituximab. CONCLUSION: The sufficient surveillance for serum EBV and repeat biopsy is necessary for patients with AITL, and this treatment modality may become an active option. © Science Printers and Publishers, Inc.