[Isolated trigeminal sensory neuropathy due to pontine infarction of the root entry zone--report of two cases].

Secondary trigeminal neuralgia and isolated trigeminal neuropathy due to ischemic lesion of the pons are very rare. We report 2 patients with pontine infarct transecting the central trigeminal pathways resulting in trigeminal neuropathy and/or neuralgia. Case 1: A 48-year-old female presented with lancinating pain and paresthesia and hypesthesia in the right V2 and V3 distributions. Magnetic resonance imaging (MRI) of the brain demonstrated a wedge-shaped infarct at the root entry zone (REZ) of the right trigeminal nerve in the pons. Case 2: A 66-year-old female presented with paresthesia and hypesthesia in the right V1, V2 and V3 distributions. MRI demonstrated a small wedge-shaped infarct at REZ. This infarction of the REZ may have led to produce the isolated trigeminal neuralgia and trigeminal neuropathy.