Eye of the tiger-like MRI in parkinsonian variant of multiple system atrophy

Abstract

Parkinsonian variant of multiple system atrophy (MSA-P) clinically presents as autonomic dysfunction with parkinsonian features. Parkinsonian features include bradykinesia, rigidity, tremor, postural instability and poor levo-dopa response. Neuropathologically, MSA-P is characterized by selective neuronal loss and gliosis mainly affecting the putamen and caudate nucleus, substantia nigra, olivopontocerebellar pathway and intermediolateral cell column of the spinal cord. Therefore, the target of magnetic resonance imaging (MRI) is focused on signal changes or volume reduction on putamen, including putaminal slit, gliosis by diffusion studies and reduction of putaminal volume. There have been no reports describing clinical manifestations of MSA-P with imaging abnormalities over globus pallidus. Here, we describe three patients with typical presentations of MSA-P with autonomic dysfunction and disturbances of axial motor function with minimal appendicular symptoms, including postural instability and gait difficulties. MRI showed symmetrical hyperintensity over the center of globus pallidus surrounded by a mild low-signal rims at T2-weighted image that is similar to that of eye of the tiger sign except for the marked hypointense rims. Dopamine transporter scans showed symmetric reduction of uptake over bilateral basal ganglia. This is the first report concerning these unusual imaging findings in MSA-P patients and we believe there is a subgroup of MSA-P with clinical presentation of axial impairment and symmetrically abnormal signal changes of globus pallidus in MRI.