Chronic Eosinophilic Leukemia Positive for FIP1L1-PDGFRa

<i>FIP1L1-PDGFRα-</i>positive chronic eosinophilic leukemia (CEL) is a rare subtype of myeloproliferative neoplasm characterized by organ damage caused by eosinophilic granules containing cytokines and humoral factors. These include interleukin-5 (IL-5), interleukin-4 (IL-4), and interleukin-13 (IL-13). We present a case study of a 71-year-old male who initially presented with cough, fever, night sweats, and weight loss. Fluorescence in situ hybridization (FISH) and cytogenetic testing confirmed that the patient had <i>FIP1L1-PDGFRα-</i>positive chronic eosinophilic leukemia. Treatment with imatinib and prednisone led to a rapid decrease in the eosinophil count without further damage from eosinophilic infiltration. Our patient has tolerated therapy with occasional lightheadedness that he attributed to external factors, and he continues to remain in remission. This case study aims to contribute to the existing knowledge regarding the discovery and treatment of this disease.