Late relapse of acute promyelocytic leukemia treated with all- trans retinoic acid and chemotherapy: report of two cases.

Two patients with acute promyelocytic leukemia (APL) relapsed at 111 and 84 months after achievement of complete remission (CR) induced by a combination of all- trans retinoic acid and chemotherapy. In both patients molecular remission, obtained after consolidation, had been confirmed at 60 months from CR achievement. At relapse, morphological, immunophenotypic, cytogenetic, and molecular analyses showed findings identical to those at diagnosis. Hematological and molecular remission was induced with the identical treatment applied at diagnosis. We conclude that, although infrequently, patients with APL treated with modern combination therapy can experience very late relapse and can be rescued with treatment similar to that administered at diagnosis.