Section Editor: Sandy Cheng-Yu Chen, M.D.
Taipei Medical University Hospital, Taipei, Taiwan
CNS myeloid sarcoma is a rare manifestation of acute myeloid leukemia. It may develop during the active phase of disease or may manifest as a relapse after months or years of clinical remission, frequently after bone marrow transplantation. The leukemic mass tends to be continuous with the meninges or ependyma and presents as an extra-axial hyperdense mass on noncontrast CT scan, with low signal intensity on T2-weighted MRI, isointense signal intensity on noncontrast T1WI (A, arrow), vivid enhancement after gadolinium administration (B, arrow), and diffusion restriction on ADC map (C, arrow).