Management of Asymptomatic Hyperleukocytosis Induced by Ibrutinib in a Patient with Chronic Lymphocytic Leukemia: A Case Study and Structured Follow-Up

Background The use of irreversible bruton tyrosine kinase inhibitors (iBTK) represented a change in the history of cancer management, thanks to higher response and maintenance rates. However, these new medications bring with them adverse effects, even putting patients' lives at risk. Case presentation : This report describes a patient with chronic lymphocytic leukemia (CLL) treated with ibrutinib who developed persistent, asymptomatic hyperleukocytosis with a maximum leukocyte count of 593.66×10⁹/L, over a two-month period. The leukocyte count gradually normalized without intervention. Conclusions The absence of established guidelines for managing such cases poses diagnostic and monitoring challenges. This case underscores the utility of expectant management and emphasizes the need for stricter leukocyte monitoring to better characterize the duration and evolution of this phenomenon. Given the limited data on hyperleukocytosis in iBTK-treated patients, further case reports are essential, not only in CLL but also in other malignancies treated with iBTKs.