Cytology
eosinophils > 5% with large immature basophilic granules
NASCA+ in the bone marrow (but normal in blood)
specific abnormal eosinophil component
immature eosinophilic granules
- mainly evident at the promyelocyte and myelocyte stages
- not usually evident at later stages of maturation
- eosinophilic granules are often larger than those normally seen in immature eosinophils, purple-violet in color and in some cells are so dense that they obscure the cell morphology
Cytogenetics
all M4eo share 16q22 anomaly
- inv(16)(p13q22)