A Rare Manifestation of CNS Leukemia: A Case Report.

Central nervous system (CNS) involvement in acute myeloid leukemia (AML) is uncommon, reported in < 3% of patients, and confers poor prognosis. We present a 71-year-old Korean woman with prior myeloid sarcoma who progressed to AML and later developed isolated CNS leukemia. Her course included pancytopenia, extramedullary skin lesions, hyperleukocytosis, transfusion-dependent anemia, and elevated LDH. Neurologic decline revealed dural lesions on imaging; cerebrospinal fluid flow cytometry confirmed CNS disease despite negative cytology. She responded to intrathecal methotrexate and high-dose cytarabine, underscoring the need for CNS-directed therapy. Myeloid sarcoma precedes AML in 2%-8% of cases, yet CNS relapse remains rare. Diagnostic challenges arise from nonspecific neuroimaging and overlap with infectious or inflammatory etiologies, highlighting the role of flow cytometry and molecular studies. Median survival after CNS relapse is reported at 3-6 months. This case also illustrates how language barriers may delay diagnosis and complicate management, emphasizing the need for accessible care frameworks.