Atypical Chronic Myeloid Leukemia, BCR-ABL1 Negative

Differential Diagnosis

Myeloproliferative and Mixed MDS/MPNs with Neutrophilia and/or Monocytosis

	CML-CP	Atypical CML	CMML-1	CNL
Ph Chromosome and/or BCR-ABL1 Translocation	Almost 100%	Absent	Absent	Absent
WBC	Left shifted neutrophilia*	Left shifted neutrophilia	Monocytosis, may have left shifted neutrophilia	Neutrophilia
Blood basophils	Increased	Not increased	Not increased	Not increased
Blood monocytes	Variable,** <1x10³/μL	Variable, <1x10³/μL	Always >1x10³/μL	<1x10³/μL
Blood immature granulocytes	>20%	10-20%	Usually <10%	<10%
Blood blasts	Usually <2%	>2%	<5%	<1%
Granulocytic dysplasia	Absent	++	+/-	Absent

*rare p230 BCR-ABL1 isoform may show mature neutrophilia, **rare p190 BCR-ABL1 isoform associated with monocytosis