Context: Progressive myelopathy can be a manifestation of a variety of disorders including progressive multiple sclerosis. However it is extremely uncommon for a single lesion to cause a progressive myelopathy in MS. Such a myelopathy, i.e. a progressive neurological deficit from a solitary demyelinating lesion, not fulfilling the International diagnostic criteria for MS or Neuromyelitis Optica was first reported in 2012 and termed 'solitary sclerosis'.
Method: We report 3 further cases of progressive myelopathy fulfilling the diagnostic criteria for solitary sclerosis.
Findings: Two patients had a single demyelinating lesion in the cervical cord and the third patient had it in the brain stem. All patients had serial MRI scans showing no dissemination or progression of lesions. Extensive diagnostic tests including aquaporin 4 antibodies were negative in all. At last follow-up at a median of 3.8 years, all patients continued to clinically progress despite immunosuppressive treatment.
Conclusion/clinical relevance: Solitary demyelinating lesions can cause a progressive myelopathy without clinical or radiological evidence of dissemination. Importantly, clinicians, both surgical and medical should be aware of such a diagnosis, to avoid invasive and often harmful tests particularly biopsies.
Keywords: Multiple sclerosis; Myelitis; Neuromyelitis optica; Progressive; Solitary sclerosis; Spinal cord tumour.