A Critical Case of Chronic Eosinophilic Leukemia: Diagnostic Criteria and Response to Cytarabine

Chronic eosinophilic leukemia (CEL) belongs to the group of chronic myeloproliferative neoplasms characterized by the persistence of an absolute eosinophil count (AEC) > 1.5 × 10⁹/L for 1-6 months and is accompanied by organ damage. The new World Health Organization criteria for the diagnosis of CEL are the presence of the cytogenetic alteration <i>FIP1L1::PDGFRA</i> as an oncogene; in its absence, morphological criteria in bone marrow define the diagnosis with blasts > 5% and < 20% and in peripheral blood with > 2% of blasts and eosinophilia >1.5 × 10⁹/L. The current study describes the case of a 60-year-old man who was admitted to the internal medicine department in critical condition with fever, cough, dyspnea, shortness of breath, and intense abdominal pain, and his spleen had the following measurements: 8-8-10 cm. The complete blood count showed hemoglobin 8.5 g/dL, platelets92 × 10⁹/L, leukocytes105.97 × 10⁹/L, total neutrophils31.79 × 10⁹/L, AEC69.40 × 10⁹/L, and lymphocytes4.23 × 10⁹/L, and the bone marrow analysis revealed 25% eosinophils and 12% myeloblasts. Thorax and abdomen computed tomography showed interstitial infiltrate, pleural effusion, and splenomegaly. Endoscopy showed ulcerative lesions in the digestive tract. This case underscores the crucial role of both bone marrow and peripheral blood morphological criteria in diagnosing CEL. This rare disease manifests at an advanced stage with complex clinical features but responds well to cytarabine.