Trigeminal neuralgia caused by contact between the affected trigeminal nerve and a space-occupying lesion.

Diagnostic criteria:
  1. Recurrent paroxysms of unilateral facial pain fulfilling criteria for 13.1.1 Trigeminal neuralgia
  2. Both of the following:
    1. a space-occupying lesion in contact with the affected trigeminal nerve has been demonstrated
    2. pain has developed after identification of the lesion, or led to its discovery
  3. Not better accounted for by another ICHD-3 diagnosis.

Patients with Trigeminal neuralgia attributed to space-occupying lesion may or may not have clinically detectable sensory signs, while electrophysiological tests such as trigeminal brainstem reflexes show abnormalities in nearly all cases.