Abstract
Large granular lymphocytic (LGL) leukemia is a rare chronic lymphoproliferative disorder originating from natural killer cells or T lymphocytes. In this report, we present the case of a 66-year-old female initially treated for sepsis, with methicillin-sensitive Staphylococcus aureus identified on initial blood culture prompting intravenous (IV) antibiotic therapy. The patient met systemic inflammatory response syndrome criteria upon admission due to severe neutropenia. Persistent fever led to neurological symptoms, and imaging revealed lung abnormalities along with chronic changes on the CT scan of the head. Multidisciplinary consultations were sought, resulting in treatment adjustments including antifungals and filgrastim. Flow cytometry and bone marrow biopsy confirmed the diagnosis of LGL leukemia.