Primary Cutaneous Epstein-Barr Virus (EBV)-Positive Diffuse Large B-cell Lymphoma With Synchronous Systemic T-cell Lymphoma: A Case Report.

Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma (DLBCL) is a rare and aggressive lymphoma that has been associated with age-related immunosenescence. Here, we present the case of a 79-year-old man with violaceous nodules on the skin, mainly on the lower and upper limbs, diagnosed as primary cutaneous EBV-positive diffuse large B-cell lymphoma (DLBCL) based on histopathological and immunohistochemical findings. Systemic evaluation revealed synchronous peripheral T-cell lymphoma, not otherwise specified (NOS), without systemic B-cell lymphoma involvement. The patient was treated with rituximab, cyclophosphamide, hydroxydaunorubicin, vincristine (Oncovin), and prednisone (R-CHOP) chemotherapy, achieving a complete response for both lymphomas, with sustained outcomes after one year of follow-up. This case highlights the importance of age as a risk factor for EBV-related malignancies, the role of Epstein-Barr encoding region (EBER) and cluster of differentiation 30 (CD30) testing in diagnosis, and the potential effectiveness of R-CHOP in treating this rare lymphoma association. Further research is needed to establish optimal management strategies.