Atypical chronic myelogenous leukemia (aCML), BCR/ABL1 negative is a rare disorder classified into the category of myelodysplastic/myeloproliferative neoplasms (MDS/MPN), according to the 2016 revision of the World Health Organization (WHO) classification of myeloid neoplasms and acute leukemia. It is, by definition, a BCR-ABL1-negative clonal disorder sharing myelodysplastic and myeloproliferative features.
Diagnostic Criteria of Atypical Chronic Myeloid Leukemia (aCML)
| Feature | WHO 2016 |
| Ph chromosome | Absent |
| BCR/ABL1 | Absent |
| Leukocytosis | Persistent (≥13×109/L) |
| Basophil count | <2% |
| Monocyte count | <10% of leukocytes |
| Multilineage dysplasia | Dyserythropoiesis and dysmegakaryopoiesis may be present |
| Dysgranulopoiesis | Present |
| Immature granulocytes | ≥ 10% leukocytes |
| Blasts | <20% (blood and bone marrow) |
| Bone marrow cellularity | Hypercellular bone marrow |
| Other molecular characteristics | No rearrangements of PDGFRA, PDGFRB, FGFR1, and PCM1-JAK2 Emphasis on molecular changes (ETNK1, SETBP1) |
| Other factors | WHO criteria for other MPNs not met |
FAB, French-American-British; WHO, World Health Organization; Ph, Philadelphia; MPN, myeloproliferative neoplasm; MPN, myeloproliferative neoplasm.
References:
- Diamantopoulos PT, Viniou NA. Atypical Chronic Myelogenous Leukemia, BCR-ABL1 Negative: Diagnostic Criteria and Treatment Approaches. Front Oncol. 2021 Nov 17;11:722507. [Medline]
- Belkhair J, Raissi A, Elyahyaoui H, Ameur MA, Chakour M. Atypical chronic myeloid leukemia BCR-ABL 1 negative: A case report and literature review. Leuk Res Rep. 2019 May 25;12:100172. [Medline]
Created Jun 24, 2022.
