We describe herein the case of a 57 year old man who, over the last five years, has presented ataxic and spastic gait on the right side, a reduction in fine motor movement of the fingers mainly on the right side, superficial right side brachiocrural hypoesthesia and a marked dysarthria associated with internuclear ophthalmoplegia. The neurological picture, after an initial progressive worsening which lasted some months, remained relatively stable over the years. Repeated magnetic resonance imaging (MRI) of the brain and spinal cord documented the presence of demyelinating plaques spread in the white matter of the periventricular region and the semioval centres, and a right side paramedian plaque at the C4-C5 level, none of which were in the active phase. Oligoclonal bands were revealed in the cerebrospinal fluid (CSF). Monoclonal IgM/lambda gammopathy with anti-myelin and anti-nucleo reactivity, found with serum immunofixation, were confirmed several times in successive annual controls, not associated to myeloproliferative pathology. The lack of progression in the clinical picture would seem to contradict the diagnosis of late Multiple Sclerosis. The presence of antibody activity against the myelin might support the hypothesis of a pathogenetic role of the immunoglobulins at the onset of the demyelinating disease in this patient. However, in the end, there is the possibility of casual association with a poorly functioning immune system connected to age.