Sequential Development of Chronic Lymphocytic Leukemia Eleven Years after Chronic Myeloid Leukemia in a Caucasian Male: A Case Report

Abstract

Aims: The coexistence of myeloproliferative and lymphoproliferative neoplasms in a single patient is extremely rare. We report a case of chronic lymphocytic leukemia (CLL) developing 11 years after successful treatment of chronic myeloid leukemia (CML), to highlight this unusual sequence and discuss its clinical implications. Presentation of Case: A 52-year-old Caucasian male initially presented with nosebleeds, fatigue, fever, and ascites. Investigations, including complete blood count, bone marrow aspiration, and fluorescence in situ hybridization confirmed chronic-phase CML with Philadelphia chromosome positivity. He was treated with imatinib 400 mg daily, achieving major molecular response (MMR) within 12 months, and remained in remission for 11 years. Subsequently, CBC showed persistent leukocytosis, prompting escalation of imatinib to 600 mg and bone marrow trephine biopsy. Biopsy revealed absolute lymphocytosis, and flow cytometry demonstrated a CD19+, CD20+, CD22+, CD5+, CD23+, CD200+ B-cell clone consistent with CLL. The patient was started on chlorambucil 4 mg with improvement. Discussion: Although secondary malignancies in CML patients are rare, long-term follow-up may reveal additional hematological neoplasms, including lymphoid lineage disorders such as CLL. Potential mechanisms include clonal evolution, genetic instability, or treatment-related effects on hematopoiesis. Conclusion: Physicians should consider the possibility of secondary lymphoid neoplasms such as CLL in patients with long-standing CML, particularly when unexpected leukocytosis or lymphadenopathy develops during follow-up. Vigilant monitoring and prompt diagnostic workup are essential for timely recognition and management of these rare but important events.