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A variant form of acute promyelocytic leukemia with marked myelofibrosis
K Fukuno1, H Tsurumi, T Yoshikawa
1Department of Internal Medicine, Kisogawa Hospital, Aichi, Japan.
Abstract:
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/mi2 intravenously; 6-mercaptopurine, 70 mg/m2 orally for 10 days; daunorubicin 40 mg/m2 intravenously for 4 days; and all-trans retinoic acid 45 mg/M2 orally between days 20 and 33. The promyelocytic leukemia-retinoic-acid receptor (PML-RAR) alpha 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 alpha fusion transcript according to RT-PCR, for 21 months. Longer follow-up will clarify the effects of autoPBSCT on prognosis in APL with MF.
Insights
This study details a variant of acute promyelocytic leukemia (APL M3v) with unique features like myelofibrosis (MF). Effective chemotherapy and stem cell transplant led to molecular remission, suggesting a positive prognosis.
Area of Science:
- Hematology
- Oncology
- Molecular Biology
Background:
- Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia.
- The French-American-British (FAB) classification M3 is the typical form of APL.
- FAB M3v is a variant of APL with distinct characteristics.
Observation:
- A case of APL M3v presented with atypical morphology, immature antigens (CD34, HLA-DR), and significant myelofibrosis (MF).
- Unlike typical APL cells, these cells expressed CD34 and HLA-DR.
- Myelofibrosis may be more common in APL M3v cases expressing these immature antigens.
Findings:
- The patient received induction chemotherapy (enocitabine, 6-mercaptopurine, daunorubicin, all-trans retinoic acid) and consolidation chemotherapy.
- The promyelocytic leukemia-retinoic-acid receptor (PML-RAR) alpha fusion transcript became undetectable by RT-PCR after initial consolidation.
- Autologous peripheral blood stem cell transplantation (autoPBSCT) was performed without complications related to MF.
Implications:
- This APL M3v variant, despite marked myelofibrosis, responded well to chemotherapy and autoPBSCT.
- The patient achieved molecular remission (negative PML-RAR alpha transcript) and remained disease-free for 21 months.
- Further follow-up is needed to confirm the long-term impact of autoPBSCT on APL with myelofibrosis prognosis.