KP1 expression of ghost Pick bodies, amyloid P-positive astrocytes and selective nigral degeneration in early onset Picks disease.

We present a patient with early-onset Pick's disease in which selective nigral degeneration, KP1 expression of ghost Pick bodies and amyloid P-positive astrocytes were found. We also review the literature on early-onset Pick's disease. A 34-year-old man showed personality change including stereotypical behavior. Muscle rigidity and spasticity developed later, and he died twelve years after the onset of his illness. The brain showed lobar cerebral atrophy prominent in the temporal lobe, and to a lesser degree in the prefrontal and orbitofrontal cortex. The substantia nigra displayed profound degeneration whereas the head of the caudate nucleus and the putamen were not so seriously affected because the neurons were preserved and only slight astrocytic proliferation was seen. Many Pick bodies were found in the hippocampal formation, and ballooned neurons (Pick cells) were dispersed throughout the cerebral cortex, subcortical grey matter and hippocampal formation. The affected white matter exhibited severe fibrillary gliosis, and numerous astrocytes positive for glial fibrillary acidic protein and microglial cells positive for CR3/43 were found in the atrophied cortical lesions. The intraneuronal Pick bodies expressed ubiquitin, neurofilament and tau, and KP1 distinctly stained ghost Pick bodies. Tau-positive astrocytes were found in the striatum, hippocampal formation, pontine tegmentum, substantia nigra and affected frontotemporal cortices. These astrocytes were also positive for amyloid P. Extensive search of the literature on early-onset Pick's disease disclosed only a few cases with selective nigral degeneration, and we failed to find any differences in duration, progression of the illness and the extent of subcortical gray matter involvement between cases of early-onset and presenile onset of Pick' s disease. We conclude that the striatopallidal and nigral system can be affected independently in Pick's disease and report new immunohistochemical findings.