A Very Rare Case of Hypereosinophilic Syndrome Secondary to Natural Killer/T-Cell Lymphoma

Abstract

Hypereosinophilic syndrome (HES) is a systemic disease characterized by an increased peripheral blood eosinophil count accompanied by systemic organ dysfunction. HES is classified into idiopathic HES, primary (neoplastic) HES (HES N ), and secondary (reactive) HES (HES R ). In this case report, a patient who developed peripheral blood eosinophilia and granulation tissue in the pharynx and paranasal sinus, which was initially diagnosed as chronic eosinophilic leukemia (CEL), categorized as HES N , but was eventually identified after the patient had died as natural killer/T-cell (NK/T) lymphoma, nasal type (ENKL), categorized as HES R , is presented. ENKL-induced HES is very rare but must be considered.