Dueling Malignancies: A Rare Case of Concurrent Chronic Lymphocytic Leukemia (CLL) and Chronic Myeloid Leukemia (CML) in a Multimorbid Elderly Patient.

The concurrent presence of multiple hematological malignancies in a single patient is exceptionally rare. Coexisting chronic lymphocytic leukemia (CLL) and chronic myeloid leukemia (CML) in an elderly patient with multiple comorbidities presented unique diagnostic and management challenges. We report a 69-year-old female with a history of type 2 diabetes mellitus, hypertension, chronic kidney disease, and ischemic heart disease. The patient initially presented to an external hospital on 5 January 2025 with shortness of breath and decreased level of consciousness. Initial laboratory investigations at the referring hospital revealed critical values with hemoglobin of 2.9 g/dL and platelet count of 9 ×10⁹/L, requiring urgent transfusion support. During hospitalization at the referring hospital, she developed acute respiratory distress necessitating endotracheal intubation. She was subsequently referred to our institution on 9 January 2025 for further hematologic evaluation. Bone marrow examination showed hypercellularity (70-80%) with trilineage hematopoiesis. Flow cytometric analysis confirmed chronic lymphocytic leukemia (CLL). Cytogenetic studies demonstrated the Philadelphia chromosome in all analyzed metaphases, establishing the diagnosis of chronic myeloid leukemia (CML). This case illustrates the rare simultaneous occurrence of CLL and CML in a patient with significant comorbidities and life-threatening cytopenia at presentation despite a history of leukocytosis and thrombocytosis. The case underscores the importance of comprehensive hematological evaluation, including flow cytometry and cytogenetic analysis, in patients with complex presentations. Managing patients with dual hematological malignancies requires careful consideration of treatment interactions, comorbidities, and complications, highlighting the need for a multidisciplinary approach to optimize outcomes.