Spontaneous remission of Epstein-Barr virus-negative non-Hodgkin's lymphoma after withdrawal of cyclosporine in a patient with refractory anemia.

A 70-year-old man presented with pancytopenia in August 2000, and the results of a bone marrow examination performed in January 2001 confirmed the diagnosis of refractory anemia. He was treated with cyclosporine (CsA) at 3.3 mg/kg per day, and the pancytopenia improved. The patient complained of epigastralgia 21 months later, and a gastric endoscopic examination showed an ulcer with a cleaved bank. A biopsy revealed diffuse large B-cell lymphoma. In situ hybridization analysis detected no Epstein-Barr virus (EBV) in the lymphoma. CsA treatment was discontinued, and a gastrectomy was performed 31 days later. A detailed histologic examination revealed no infiltration of abnormal B-cells in the resected stomach. Although EBV-positive lymphoma is a known complication of immunosuppressive therapy, no causal association between immunosuppressants and EBV-negative lymphoma has been established. The spontaneous remission observed after the withdrawal of CsA treatment suggests that immunosuppressive therapy can be a pathogenic factor in a subset of EBV-negative lymphomas.