Chronic Eosinophilic Leukemia, NOS
Definition
- Clonal, persistent eosinophilia not attributable to defined translocations listed below
Diagnostic Criteria
- All of the following must be demonstrated
- Persistent peripheral blood eosinophilia ≥1.5 x 103/μL
- Eosinophils may be morphologically abnormal
- May have nuclear enlargement, hyper or hyposegmentation
- Cytoplasmic clearing or vacuolation
- Eosinophils may be morphologically abnormal
- If monocytes >1 x 103/μL consider CMML
- If neutrophil precursors >10% or dysplastic, consider atypical CML
- Reactive (allergy etc.) and secondary (T cell lymphoma etc.) eosinophilia should be excluded (see Differential Diagnosis)
- Must have either:
- Evidence of clonality
- But must not have:
- BCR-ABL1 (CML)
- PDGFRA, PDGFRB or FGFR1 abnormalities (Hematolymphoid neoplasms with PDGFR/FGFR Abnormalities
- inv or t(16)(p13.1,q22) (Acute Myelogenous Leukemia)
- But must not have:
- OR increased myeloblasts
- Peripheral blood >2% but <20%
- OR bone marrow >5% but <20%
- If neither of these two are present, but there is persistent (6 month) eosinophilia with tissue damage, designate as Idiopathic Hypereosinophilic Syndrome
- Peripheral blood and bone marrow myeloblasts must be <20%
- If ≥20% consider Acute Myelogenous Leukemia
- Persistent peripheral blood eosinophilia ≥1.5 x 103/μL
- May have evidence of organ involvement with tissue damage (see Clinical)
- Some cases may have an abnormal T cell population which may be clonal
- Designated "lymphocyte variant hypereosinophilia", a poorly defined entity
Dita Gratzinger MD PhD
Tracy I George MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting: 10/23/11
