Action at a distance: a lumbar spine tumor presenting as trigeminal neuralgia.

Trigeminal neuralgia (TN) is often secondary to an underlying structural cause, frequently compression of the fifth nerve root by an ectatic artery. Here we describe a case of a 36-year-old woman with symptoms of TN who was found to have severe communicating hydrocephalus. Further investigation revealed a lumbar myxopapillary ependymoma, which in turn was responsible for the communicating hydrocephalus. An argument connecting these seemingly disparate findings is made. This unusual set of circumstances is an example of "action at a distance" in the nervous system, and reminds clinicians to think broadly about the various pathophysiologic mechanisms that can potentially underlie common disorders.