Most physicians in general, and neurologists in particular, enjoy tackling challenging clinical cases; making the correct diagnosis can be quite satisfying. However, primary brain tumors may present with nonspecific or subtle signs that can sometimes be missed or misinterpreted. More than ever, brain imaging has improved our ability to correctly diagnose and care for patients with brain tumors. We have included some cases from the Department of Neurology at Memorial Sloan-Kettering Cancer Center (New York, NY) to help illustrate some "pearls" when considering the diagnostic possibility of a brain tumor.