Atypical chronic myeloid leukemia (aCML)
- Method:
- Anticoagulant:
- Recommendation:
- Method:
- Anticoagulant:
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- Method:
- Anticoagulant:
- Recommendation:
- Method:
- Anticoagulant:
- Recommendation:
- Method:
- Anticoagulant:
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- Method:
- Anticoagulant:
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BCR-ABL1-negative atypical chronic myeloid leukemia (aCML) is a rare entity from the overlapping area of myelodysplastic and myeloproliferative diseases.
aCML - Classification
According to the WHO classification 2017, aCML is a leukemic disorder with myelodysplastic as well myeloproliferative features (MDS/MPN).
aCML WHO Classification 2017 (Swerdlow et al. 2017)
Myelodysplastic/myeloproliferative neoplasia
Atypical chronic myeloid leukaemia (aCML), BCR-ABL1-negative
Diagnostic criteria according to WHO 2017:
- Peripheral blood leukocytosis ≥ 13x109/L, due to increased numbers of neutrophils and their precursors (i.e. promyelocytes, myelocytes and metamyelocytes), with neutrophil precursors constituting > 10% of the leukocytes
- Dysgranulopoiesis, which may include abnormal chromatin clumping
- No or minimal basophilia; basophils constitute < 2% of the peripheral blood leukocytes
- No or minimal monocytosis; monocytes constitute < 10% of the peripheral blood leukocytes
- Hypercellular bone marrow with granulocyte proliferation and granulocytic dysplasia, with or without dysplasia in the erythroid and megakaryocytic lineages
- <20% blasts in the blood and bone marrow
- No evidence of PDGFRA, PDGFRB or FGFR1 rearrangement, or of PCM1-JAK2
- WHO criteria for BCR-ABL1-positive CML, PMF, PV or ET are not met
Diagnostics of aCML
Prognosis of aCML
A leukocyte count of >50x109/L has been described in several studies as a prognostically negative parameter for aCML (Onida et al. 2002, Breccia et al. 2006, Wang et al. 2014). In some of these studies, an age >65 years, female sex and a hemoglobin level of <10 g/dL were also prognostically unfavourable. Furthermore, a negative influence of a SETBP1 mutation was shown (Piazza et al. 2013). 30-40% of patients with aCML show a transformation into AML (Wang et al. 2014).
aCML - Recommendation
It should be noted that according to WHO 2017, within the framework of differential diagnoses, a CNL should be morphologically excluded if a CSF3R mutation is detected. Similarly, in the case of detection of a JAK2, CALR or MPL mutation, an accelerated phase of an MPN should be excluded based on the history.
In contrast, according to WHO 2017, the presence of a SETBP1 or ETNK1 mutation supports the diagnosis of atypical CML.