Expanding the spectrum of the giant panda sign: a bright-eye variant in Wilson disease.

Wilson disease is an autosomal recessive disorder that affects copper metabolism due to mutations in the ATP7B gene. It causes problems with the liver and the nervous system. On magnetic resonance imaging (MRI), the typical sign is the "face of the giant panda" in the midbrain. A rarer sign, called the "panda with bright eyes," suggests more extensive brainstem involvement and is not often seen. A 21-year-old man developed worsening behavior changes, mood swings, and trouble with his studies. He later had tremors in both arms and mild speech difficulties. His liver tests were abnormal, and his ceruloplasmin level was low at 8 mg/dL. An eye exam showed Kayser-Fleischer rings in both eyes. Brain MRI showed symmetrical T2/FLAIR hyperintensities in the caudate nuclei, putamina, globus pallidi, thalami, posterior limbs of the internal capsules, and both the superior and middle cerebellar peduncles, as well as the pons. Increased T2 signal in the red nuclei and substantia nigra produced the "panda with bright eyes" sign. There was also diffusion restriction in both globus pallidi and thalami. The Leipzig score confirmed Wilson disease. The patient started D-penicillamine treatment and showed clinical improvement. Radiologists need to recognize both common and rare MRI features of Wilson disease, especially when neuropsychiatric symptoms are present. Spotting the "panda with bright eyes" sign can help with early diagnosis, guide metabolic testing, and allow prompt chelation therapy, which can improve neurological outcomes.