Trigeminal neuralgia as initial symptom of paramedian tentorial meningioma.

Posterior cranial fossa tumours, not involving the cerebellopontine angle cistern, are a rare cause of trigeminal neuralgia (TN). We describe a patient with a large paramedian tentorial meningioma associated with acquired Chiari malformation who presented with TN. Trigeminal pain resolved after gross total tumour resection and postoperative magnetic resonance images disclosed a minimal residual tumour in the torcular region as well as ascent of cerebellar tonsils. In this article, we investigate the physiopathological hypotheses for this unusual association with emphasis on the role of tonsillar prolapse as neuropathological basis of neuropathic pain in this patient.