Abstract
Eosinophilia is a notable feature in various hematological malignancies, including specific types of leukemias and lymphomas that may occur in the head and neck. In hematologic malignancies, eosinophilia can be primary, driven by genetic abnormalities, or secondary, resulting from cytokine and chemokine production by the neoplastic cells or the tumor microenvironment. This review examines the association between eosinophilia and head and neck hematolymphoid malignancies including Classic Hodgkin lymphoma, T-cell lymphoblastic leukemia, mature T and NK-cell lymphomas, and Langerhans cell histiocytosis. It explores the underlying mechanisms of eosinophilia in these malignancies, highlighting the role of chemokines and cytokines such as IL-5, TARC, and eotaxin. Recognition of eosinophilia may aid in the diagnosis of these conditions and understanding the mechanisms of eosinophilia may provide insights into potential prognostic implications and treatment strategies.