Chronic Eosinophilic Leukemia, Not Otherwise Specified (CEL, NOS)

Chronic eosinophilic leukemia, NOS (CEL, NOS) is considered a myeloproliferative neoplasm and is defined as a clonal proliferation of eosinophil precursors. This review presents the definition and characteristic cytomorphological, immunophenotypic, cytogenetic, and molecular features of CEL, NOS and discusses in depth the differential diagnoses. Following this presentation, the review then focuses on therapeutic approaches, including targeted therapy.