A clinical-pathological study is presented concerning a patient affected by a demential syndrome at a young age (32 years). The neurological examination of the patient disclosed an asymmetry of the deep reflexes and a pale optic disk in both eyes. The pathological examination showed a typical MS, with extensive involvement of the frontal lobes. From our case and from those rarely reported in the literature, it appears that a demential syndrome can rarely be symptomatic of an initial MS. However even in these exceptional cases some neurological signs suggestive of MS are usually present.