The “double panda sign” and central pontine signal changes in Wilson’s disease

Clinical History

A female patient of 28 years of age was admitted to the hospital for hand tremor, ataxia, slurred speech and bipolar disorder. Few years later, her younger sister presented to the emergency department with the same symptoms. Brain-MRI was conducted in both women at the time of each hospitalization.

Imaging Findings

The first woman’s brain-MRI revealed bilateral, symmetric T2-hyperintensities of the basal ganglia and hyperintensity of the midbrain with the characteristic “face of the giant-panda”, created by high-signal intensity in the tegmentum except the red nucleus (“eyes”), preservation of signal intensity in the lateral portion of the pars reticulata of the substantia nigra (“ears”) and hypointensity in the superior colliculus (“mouth”) (Fig.1, 2). The younger sister’s brain-MRI revealed hyperintensities in the pons, a feature also described in Wilson disease, and the “face of the miniature panda” within the pontine tegmentum. It is delineated by the relative hypointensity of the medial longitudinal fasciculi and central tegmental tracts (“eyes ”) in contrast with the hyperintensity of the aqueduct opening into the fourth ventricle (“nose and mouth”) (Fig.3, 4). Eye examination depicted Kayser-Fleischer rings in the cornea of the eyes of both patients. Levels of ceruloplasmin in the blood, copper in a 24 hours urine sample and liver biopsy proved the nature of their disease.

Discussion

Wilson disease is a rare autosomal recessive disorder of abnormal copper accumulation in tissues, caused by mutations in ATP7B gene. Total body copper is elevated and deposition in Golgi complexes and mitochondria results in oxidative damage through Fenton’s process to the liver, brain, eyes, kidneys and skeletal system [1]. The predominant site that is affected in the brain is the basal ganglia and features of the insult include oedema, necrosis and spongiform changes leading to volume loss. Variable gliosis and demyelination appear within the white matter of the cerebral and cerebellar hemispheres. The pathologic characteristics are illustrated by MRI sequences as bilateral, symmetric T2 and FLAIR hyperintensities and T2* blooming in the putamina, the caudate nuclei, the ventrolateral thalami and the midbrain. Pons, medulla and cerebellum may also demonstrate hyperintensities, whereas the cerebral and cerebellar white matter hyperintensities can be focal or diffusely confluent. T1 signal intensity may be variable. Restricted diffusion may be seen in the early course of the disease. A special imaging characteristic of Wilson’s disease is termed “the face of the giant panda”, which is a feature resulting from the sparing of the red nuclei within a diffuse midbrain hyperintensity. “The face of the giant panda sign” was first described by Hitoshi et al. in 1991. [2] Sometimes, in addition to that feature, a “miniature panda face” can be seen in the pontine tegmentum, created by hypointensity of the central tegmental tracts and hyperintensity of the aqueduct opening to the fourth ventricle. Furthermore, diffuse pontine changes in Wilson disease are similar to those of central pontine myelinolysis, and atrophy changes in the basal ganglia, brainstem and cerebellum (71-82%) and high signal intensity of the basal ganglia on T1w images (45%) have also been described. Clinical and MR imaging improvement occurred in 80% of patients with effective de-coppering treatment [3-6].

Differential Diagnosis List

Final Diagnosis

Wilson disease

URL:	https://www.eurorad.org/case/12887
DOI:	10.1594/EURORAD/CASE.12887
ISSN:	1563-4086