A Case of Primary Lateral Sclerosis Showing Degeneration ofCorticospinal Tract on Magnetic Resonance Imaging

ABSTRACT

Primary lateral sclerosis (PLS) is a rare upper motor neuron disease characterized by selective degeneration of corticospinal and corticobulbar tracts. It is important to rule out other diseases presenting as progressive spastic paraparesis, such as multiple sclerosis (MS) or amyotrophic lateral sclerosis (ALS). Though that is not so difficult as the development of imaging technique and neurophysiological tool, if one shows slow progressive spastic paraparesis clinically, and there is no abnormal CSF or EMG findings, it is not easy to differentiate between primary progressive MS and PLS. In fact, PLS is so rare that it has long been debated whether PLS is a disease entity or syndrome or a nothing. But we present a PLS patient whose brain MRI shows diffuse signal change along the bilateral corticospinal tracts and the hypoperfusion of frontal motor cortex is proved by brain SPECT.