The spinal cord can be affected by multiple heterogeneous disorders often difficult to diagnose. We describe ten patients affected by a progressive ascending myelopathy with a poor prognosis. The patients, during the follow-up period, underwent neurological examinations, cerebrospinal fluid analysis, hematological, microbiological, auto-antibodies screening, brain and spinal cord magnetic resonance imaging (MRI) and electroneurophysiological study. At disease onset spinal cord MRI showed ≥1 myelopathic lesions extended for <2 segments and then evidenced a progressive spinal cord atrophy without any new lesion. All patients showed an increase of the visual evoked potential P100 latency. All of them showed two or more clinical recurrences of myelitis and then, after a period ranging from 3 to 5 years from the disease onset, a progressive course. Five patients became unresponsive to intravenous high-dose steroid treatments and/or intravenous immunoglobulins and to any other therapeutic attempts, developed a progressive ascending myelopathy to tetraplegia and died from respiratory failure. The other five patients are in progressive phase of the disease with an initial involvement of the upper limbs and show mild cervical spinal cord atrophy at MRI, configuring the early stage of an ascending progressive myelopathy. In our opinion, the more suitable diagnosis is an atypical form of MS although is not possible to exclude a new nosological entity that could be included in the expanding range of spinal cord diseases.