A case of presumptive primary lateral sclerosis with upper and lower motor neurone pathology

Motor Neurone Disease (MND) is one of the commonest neurodegenerative disorders of adulthood. MND characteristically presents with a combination of both upper and lower motor neurone features. Primary Lateral Sclerosis (PLS) is thought to be a variant of MND presenting with purely upper motor neurone signs. Debate continues over whether PLS constitutes a distinct pathological entity or whether it is part of the spectrum of motor neurone diseases that present as an upper motor neurone-predominant form of MND. We present a case of MND with purely upper motor neurone features and a prominent pain component. A pre-mortem diagnosis of PLS was made, however autopsy findings demonstrated both upper and lower motor neurone involvement. We believe these findings support the view that PLS is not a discrete pathological entity, but that it is a part of the range of motor neurone diseases that present with predominant but not exclusive upper motor neurone involvement. This case also highlights the feature that pain may be associated with MND even though it is not appreciated to have a sensory pathology.