A Variant Form of Acute Promyelocytic Leukemia With Marked Myelofibrosis

We describe a variant form, French-American-British (FAB) M3v, of acute promyelocytic leukemia (APL; FAB M3) with atypical morphocytochemical features, immature antigens (CD34 and HLA-DR) and marked myelofibrosis (MF). Usual APL cells do not express CD34 or HLA-DR antigens. MF may be more frequently observed in patients with M3v expressing CD34 and HLA-DR antigens than in patients with M3 lacking these antigens. Despite marked MF, recovery from the hypoplastic phase in the case we described was not delayed after remission induction chemotherapy consisting of enocitabine, 200 mg/mp2 intravenously; 6-mercaptopurine, 70 mg/mp2 orally for 10 days; daunorubicin 40 mg/mp2 intravenously for 4 days; and all-trans retinoic acid 45 mg/mp2 orally between days 20 and 33. The promyelocytic leukemia-retinoic-acid receptor (PML-RAR) α fusion transcript, according to reverse transcriptase-polymerase chain reaction (RT-PCR), became negative in the bone marrow after the first course of consolidation chemotherapy. Autologous peripheral blood stem cell transplantation (autoPBSCT) was carried out after 3 courses of consolidation chemotherapy. There were no specific complications based on MF throughout the clinical course, including engraftment in autoPBSCT. The patient has been without MF and in molecular remission, defined as disappearance of the PML-RAR α fusion transcript according to RT-PCR, for 21 months. Longer follow-up will clarify the effects of autoPBSCT on prognosis in APL with MF.