In this Neurology Grand Rounds session, Meridale Baggett, MD, Massachusetts General Hospital, Harvard Medical School, presents a case of a 64-year-old woman who experienced 6 weeks of headaches, cognitive impairment, and memory loss. Shamik Bhattacharyya, MD, MS, neurologist, Brigham & Women’s; Samantha Champion, MD, neuropathology fellow, Mass General; Bart Chwalisz, MD, neurologist, Mass General; and Ramon Gonzalez, MD, PhD, Neuroradiologist, Mass General, discuss radiology studies, causes, management, and follow-up for this patient.