Central nervous system involvement as a presenting feature of acute monocytic leukemia: preceding leukemia by 12 months.

This report describes a patient who presented with a diffuse malignant central nervous system (CNS) process composed of cells with monocytic differentiation one year before the development of acute monocytic leukemia. A similar presentation has been documented for acute lymphocytic leukemia, but to the best of our knowledge, this is the first report to detail a diffuse CNS malignancy as the presenting symptom for acute monocytic leukemia.