B-cell lymphoma developing de novo hepatitis B after salvage therapies including rituximab through seroconversion of surface antibody.

: The patient was a 73-year-old woman. At 63 years of age, she had developed follicular lymphoma that showed a complete response to R-CHOP therapy. Over the subsequent 8 years, she experienced 4 relapses and was administered rituximab monotherapy once, combined rituximab-fludarabine therapy twice, and CHASE-R therapy once, achieving a complete response each time. Before her first therapy, hepatitis B virus (HBV) surface antigen was negative, while hepatitis B surface antibody (anti-HBs) and hepatitis B core antibody were not measured. Later, before her second salvage therapy, anti-HBs was negative, but then changed to positive before her third salvage therapy. HBV-DNA was negative before CHASE-R therapy. At 16 months after completing the CHASE-R therapy, she developed hepatitis and HBV-DNA had changed to positive. Hepatitis did not become fulminant and entecavir administration was effective. It was surmised that HBV had resolved, but she became negative for anti-HBs following the rituximab-containing chemotherapy. Therefore, this is a rare case in which de novo hepatitis developed after the final chemotherapy. The prognosis of patients with de novo hepatitis accompanying treatment of B-cell lymphoma is poor. In those who undergo lymphoma salvage therapy, the risk for and clinical course of HBV reactivation might differ from those of treatment-naive patients.