A complete remission can be achieved despite persistence of abnormal bone marrow promyelocytes in acute promyelocytic leukemia: experience in 2 patients

Acute promyelocytic leukemia (APL) is a distinct subset of acute myeloid leukemia (AML) and is distinguished from other subsets of AML by its distinctive morphology, specific chromosomal abnormality, associated consumptive coagulopathy, and response to treatment. Interestingly, patients with APL frequently enter complete remission without undergoing a characteristic period of bone marrow hypoplasia. In two cases in this report, complete remission was achieved without bone marrow hypoplasia without further additional course of chemotherapy despite the appearance of persistent malignant cells in the bone marrow after first induction chemotherapy. During the period of treatment, severe coagulopathy occurred in both cases but resolved as the patients entered into remission. Remission in patients with APL may occur even when induction therapy fails to cause marrow hypoplasia or to eradicate replicative cells. To avoid unnecessary exposure to toxic therapy, caution should be exercised in assessing the adequacy of remission induction treatment.