Pseudo-eye-of-the-tiger sign in cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS)

Abstract

The well-known eye-of-the-tiger sign features bilateral and symmetrical changes in the globus pallidus, with a central area of high signal and peripheral low signal on T2-weighted MRI. Although formally considered pathognomonic of pantothenate kinase-associated neurodegeneration (PKAN), there are other neurodegenerative or genetic diseases showing similar findings. Cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS) is a late-onset ataxia, that was recently associated with biallelic AAGGG repeat expansion in the RFC1 gene. Although its predominant MRI finding is cerebellar atrophy, there may be other less common associated findings. Our aim is to present two cases of CANVAS with associated (pseudo-)eye-of-the-tiger sign, highlighting the possibility of yet another differential diagnosis for this imaging sign.

Keywords: CANVAS; MRI; PKAN; eye-of-the-tiger sign; pantothenate kinase-associated neurodegeneration; pseudo-eye-of-the-tiger sign.