Trochlear Schwannoma Presenting with Isolated Trigeminal Neuralgia

Area of Science:

• Neurosurgery
• Neuropathology
• Ophthalmology

Background:

• Schwannomas originating from cranial nerves controlling eye movements are exceptionally rare.
• Typical presentations involve some degree of diplopia due to extraocular muscle dysfunction.

Observation:

• A 50-year-old woman presented with isolated trigeminal neuralgia, a highly atypical symptom.
• Imaging revealed a mass in the left ambient cistern, surgically resected via a retrosigmoid approach.

Findings:

• The mass was identified as a trochlear schwannoma compressing the trigeminal nerve's dorsal root entry zone.
• Pathological confirmation and gross total resection were achieved.
• Post-operative follow-up showed complete resolution of facial pain and intact extraocular movements.

Implications:

• This case represents the first reported instance of trochlear schwannoma manifesting primarily as trigeminal neuralgia.
• It expands the known clinical spectrum of trochlear nerve schwannomas.
• Highlights the importance of considering rare diagnoses in atypical presentations.