[Long-term remission of non-Hodgkin lymphoma secondary to the treatment for essential thrombocythemia].

A 45-year-old woman was diagnosed with essential thrombocythemia (ET) in August 1987 and received treatment with alkylating agents (total administration dose, busulfan 378 mg, MCNU 700 mg) because of a history of myocardial infarction. In June 2000, anemia gradually progressed. A few blast cells were detected in the peripheral blood at that time. Since bone marrow biopsy revealed myelofibrosis, she received anabolic hormone therapy. She was admitted to our hospital for an evaluation of abdominal distension in February 2003. Swelling of a large paraaortic lymph node of 6 cm in diameter was detected by CT scan. Lymph node biopsy revealed diffuse large B-cell lymphoma. Lymphoma cells were positive for CD10, CD19, CD20 and kappa-chain. The clinical stage was I. Complete remission has been achieved for 57 months after treatment with combination chemotherapy combined with rituximab followed by local radiation therapy. Non-Hodgkin lymphoma secondary to ET is a rare event. Such cases should therefore be accumulated to evaluate the mechanism of onset and clinical characteristics of lymphoma secondary to ET.