Trigeminal neuralgia in a patient with Dandy-Walker malformation.

BACKGROUND Trigeminal neuralgia may be idiopathic or secondary to a number of cranial pathologies. We report a novel case of trigeminal neuralgia associated with Dandy-Walker malformation, which may be an etiologic factor. CASE DESCRIPTION A 32-year-old male presented with shock-like pain in the somatosensory distribution of the right trigeminal nerve, which was refractory to all medication. MRI revealed a cystic lesion in the posterior fossa and a hypoplastic vermis. The pain was diagnosed as trigeminal neuralgia and was thought to be secondary to the Dandy-Walker malformation. The trigeminal neuralgia was treated successfully with radiofrequency thermocoagulation rhizotomy (RF-TR). CONCLUSION Trigeminal neuralgia may be associated with Dandy-Walker malformation, however an etiological relationship is not proven. We suggest that traction on the trigeminal nerve may be significant. The posterior fossa cyst of Dandy-Walker malformation may be a complicating factor when considering microvascular decompression to treat the trigeminal neuralgia. Collapse of the cyst at surgery may destabilize the posterior fossa and further deform the trigeminal nerve. We suggest that RF-TR, which is minimally invasive and reliable, may be preferable.