Eosinophilia in Hematologic Disorders.

Eosinophilia in the peripheral blood can be the manifestation various medical conditions, including benign or malignant disorders. There are 3 main types of eosinophilia-associated myeloid neoplasms (MN-eos): myeloid and lymphoid neoplasms, chronic eosinophilic leukemia not otherwise specified, and idiopathic hypereosinophilic syndrome (HES). Imatinib mesylate has revolutionized the treatment of molecularly defined MN-eos, and novel agents have been successfully used to treat HES. The discovery of new, recurrent molecular alterations in patients with MN-eos may improve their diagnosis and therapy. This review focuses on the hematologist's approach to a patient with eosinophilia and treatment options for those with eosinophilic myeloid neoplasms.