Eye-of-the-Tiger Sign: A Case Report of a Key MRI Clue to Pantothenate Kinase-Associated Neurodegeneration in an Eight-Year-Old Girl

Pantothenate kinase-associated neurodegeneration (PKAN) is an autosomal recessive disorder and the most common form of neurodegeneration with brain iron accumulation (NBIA), whose imaging hallmark is the "eye-of-the-tiger" sign of the globus pallidus on brain MRI.We report the case of an eight-year-old girl, born to first-cousin parents, with a history of delayed walking and language acquisition, who presented with a four-month history of worsening gait instability and frequent falls.Neurological examination revealed dysarthria, lower-limb dystonia, postural tremor, brisk deep tendon reflexes, and bilateral extensor plantar responses.Brain MRI at 1.5 T showed bilateral, symmetric T2 hypointensity of the globus pallidus surrounding a central hyperintense focus, consistent with the eye-of-the-tiger sign, with marked pallidal signal loss on susceptibility-weighted imaging (SWI).The substantia nigra, dentate nuclei, cerebellum, and remaining brain parenchyma were normal, as were serum copper, ceruloplasmin, and lactate levels.This combination of a progressive extrapyramidal and pyramidal syndrome with the eye-of-the-tiger sign pointed to PKAN, pending genetic confirmation.This case shows that recognizing this sign on MRI allows the radiologist to suggest the diagnosis and guide targeted genetic testing.Although highly suggestive, the sign is not pathognomonic, and confirmation requires identification of biallelic pathogenic PANK2 variants.