Of dots and levels: a case of partial subacute combined degeneration.

Subacute combined degeneration of the spinal cord is a typical clinical syndrome due to vitamin B12 deficiency, characterised by the involvement of the posterior column and corticospinal tracts. Occasionally, it may present with atypical features such as a sensory level and Lhermitte's sign, both traditionally considered to be a feature of compressive myelopathy. Spinal magnetic resonance imaging strongly augments the diagnosis by exhibiting changes in the posterior column in the form of a 'dot'. We describe such a patient who responded to therapy.