Meningocele is recognized as a rare, usually asymptomatic condition not associated with acute neurologic symptoms. We herein describe the case of a patient with a longstanding history of a lower back "mass" and recurrent syncope who became acutely unresponsive and developed bilateral retinal hemorrhages when she was placed in the supine position to undergo carotid sonography. MR imaging revealed a large, dorsal lumbar meningocele. The episode likely was caused by acutely increased intracranial pressure caused by displacement of CSF from the meningocele intracranially.