Atypical Chronic Myeloid Leukemia, BCR-ABL1 Negative
Supplemental Studies
Special stains- Nonspecific esterase, and CD68PG may be useful for identifying monocytes in tissue sections (to exclude CMML)
Genetic studies
- Ph chromosome, BCR-ABL1, PDGFRA, PDGFRB translocations must not be present
- Nonspecific karyotypic abnormalities and/or mutations are present in most cases
- Most frequent cytogenetic abnormalities include +8 and del(20q)
- Mutations in NRAS and KRAS may be present; JAK2 V617F generally absent
| Disorder | Molecular or Cytogenetic Alteration | Test Used |
|---|---|---|
| Chronic myelogenous leukemia | BCR-ABL1 | CG, FISH, PCR on PB or BM |
| Hematolymphoid neoplasms with eosinophilia and PDGFR/FGFR abnormalities | FIP1L1-PDGFRA (usually CEL) ETV6-PDGFRB (usually CMML with eosinophilia) FGFR1 (various) PDGFRa/b (various) |
CG, FISH |
| Chronic eosinophilic leukemia NOS | none specific, may have clonal CG abnormalities | CG |
| Mastocytosis | KIT D816V | CG, PCR on BM, not PB |
| Acute myelogenous leukemia, even if <20% blasts | inv or t(16)(p13.1q22); CBFB-MYH11 or t(8;21)(q22;q22) RUNX1-RUNX1T1 | CG, FISH |
