Severe brain atrophy in a case of thalamic variant of sporadic CJD with plaque-like PrP deposition.

A 30-year-old woman presented with ataxic gait and progressive mental deterioration, and 3 years later developed myoclonus in the limbs. Subsequently, she lapsed into an akinetic state and died more than 6 years after the onset of disease. The brain weighed 670 g, and preferential degeneration was found in the medial thalamus and the inferior olivary nucleus. In the cerebrum and cerebellum, gliosis and neuronal depletion were only mild and disintegration of the parenchymal structures was inconspicuous, despite pronounced atrophy. The patient had methionine homozygosity at codon 129 of the PrP gene and protease-resistant PrP type 2 in the brain. On PrP immunostaining, plaque-like deposits were detected in the cerebral and cerebellar cortices. Severe brain atrophy such as in the present case has never been described in the thalamic variant of sporadic CJD.