A case of KSHV/HHV8-positive large B-cell lymphoma in a background of HIV-negative KSHV/HHV8-positive Multicentric Castleman disease.

Lymphoproliferative disorders associated with human herpes virus 8 (HHV8) include Kaposi's sarcoma-associated herpesvirus (KSHV)/HHV8-positive multicentric Castleman disease (MCD), primary effusion lymphoma (PEL)/extracavitary PEL (EC-PEL), and KSHV/HHV8-positive diffuse large B-cell lymphoma (DLBCL). These lymphoproliferative disorders occur primarily in patients with HIV infection and immunodeficiency. HIV-negative KSHV/HHV8-positive MCD is extremely rare in Japan. We encountered a patient with KSHV/HHV8-positive large B-cell lymphoma with a history of HIV-negative, KSHV/HHV8-positive MCD. Although the KSHV/HHV8-positive MCD was in long-term remission with rituximab treatment, the patient developed refractory KSHV/HHV8-positive large B-cell lymphoma four years after the onset of MCD. The KSHV/HHV8-positive large B-cell lymphoma was refractory to chemotherapy, and the patient died. The course of this case suggests that HIV-negative KSHV/HHV-8-positive MCD may eventually lead to refractory KSHV/HHV8-positive large B-cell lymphoma, even after long-term remission with rituximab therapy.