Progressive solitary sclerosis: Gradual motor impairment from a single CNS demyelinating lesion.

OBJECTIVE: To report patients with progressive motor impairment resulting from an isolated CNS demyelinating lesion in cerebral, brainstem, or spinal cord white matter that we call progressive solitary sclerosis. METHODS: Thirty patients were identified with (1) progressive motor impairment for over 1 year with a single radiologically identified CNS demyelinating lesion along corticospinal tracts, (2) absence of other demyelinating CNS lesions, and (3) no history of relapses affecting other CNS pathways. Twenty-five were followed prospectively in our multiple sclerosis (MS) clinic and 5 were identified retrospectively from our progressive MS database. Patients were excluded if an alternative etiology for progressive motor impairment was found. Multiple brain and spinal cord MRI were reviewed by a neuroradiologist blinded to the clinical details. RESULTS: The patients' median age was 48.5 years (range 23-71) and 15 (50%) were women. The median follow-up from symptom onset was 100 months (range 15-343 months). All had insidiously progressive upper motor neuron weakness attributable to the solitary demyelinating lesion found on MRI. Clinical presentations were hemiparesis/monoparesis (n = 24), quadriparesis (n = 5), and paraparesis (n = 1). Solitary MRI lesions involved cervical spinal cord (n = 18), cervico-medullary/brainstem region (n = 6), thoracic spinal cord (n = 4), and subcortical white matter (n = 2). CSF abnormalities consistent with MS were found in 13 of 26 (50%). Demyelinating disease was confirmed pathologically in 2 (biopsy, 1; autopsy, 1). CONCLUSIONS: Progressive solitary sclerosis results from an isolated CNS demyelinating lesion. Future revisions to MS diagnostic criteria could incorporate this presentation of demyelinating disease.