Primary brain stem tethering: a rare cause of geniculate neuralgia

This rare case of brain stem tethering presented with chronic and progressi ve geniculate neuralgia. In view of the fact that an occipital subcutaneous lipoma had been resected in childhood, it probably concerned a primary tet hering, fitting in with an occult occipital dysraphism. Magnetic resonance imaging (MRI) clearly demonstrated an underlying tetheri ng, causing a distortion of the brain stem. Consequently, this led to the h ypothesis that the geniculate neuralgia could be explained by traction on t he lower cranial nerves secondary to the brain stem displacement. Untetheri ng resulted in a considerable decrease of the neuralgia. MRI proved to be essential in the diagnosis and treatment of this unusual c ase.