Introduction: This case highlights the potential importance of new-onset headache, even in the absence of other worrisome features, in a patient with a cerebral aneurysm.
Case Presentation: A 61-year-old Caucasian woman presented with nonspecific insidious onset of headache, a superior cerebellar artery aneurysm and cerebrospinal fluid lymphocytosis. She had a subarachnoid hemorrhage 21 days later, at which time the aneurysm had enlarged.