Typical trigeminal neuralgia is characterised by recurring, paroxysmal, lancinating, shock-like pain within the distribution of one or more branches of the trigeminal nerve. Light tactile stimulation may trigger such an attack. Although the contribution of central and peripheral mechanisms to the aetiopathogenesis of trigeminal neuralgia still remains unclear, the concept of vascular compression of the trigeminal root as the main causal factor in idiophatic "tic douloureux" has achieved widespread acceptance. Trigeminal neuralgia may also afflict patients with multiple sclerosis. In these cases, the demyelination of central trigeminal pathways is the accepted aetiology, and the presence of a T2 hyperintensity along the intrapontine course of trigeminal fibres is generally considered a contraindication to microvascular decompression. We recently saw a case of successful microvascular decompression in a patient without multiple sclerosis, despite an intrapontine trigeminal lesion. This 66 year old previously healthy man presented with a 6 year history of intense, paroxysmal, electric shock-like pain in the territory of the second branch of the right trigeminal nerve. The pain was triggered by washing his face and shaving and it lasted for a few seconds. Painful attacks, initially rare, gradually increased in frequency and intensity and spread to the first trigeminal branch. ...