Filum ependymoma mimicking spontaneous intracranial hypotension.

A 34-year-old man with a 2-week history of orthostatic headaches and a "dry tap" at lumbar puncture was found to have a lumbar intradural mass on magnetic resonance imaging (MRI) examination. A myxopapillary ependymoma was resected and the patient's headache completely resolved. The combination of spontaneous orthostatic headaches and a "dry tap" at the time of lumbar puncture does not always indicate the presence of a spontaneous cerebrospinal fluid (CSF) leak and intracranial hypotension.