Frontotemporal Dementia, Pick Disease, and Corticobasal Degeneration

Pick disease(PiD), or circumscribed atrophy, as Pick called it, is like the proverbial elephant. When blind men are asked to define it, one feeling a leg calls it a tree, another touching the trunk declares it a snake, and a third encountering the body calls it a wall. The term means different things to different people. Pick disease is used either to designate clinically defined cases of progressive frontal and temporal degeneration, as was described by Pick,1or a pathologic entity defined histologically by the presence of argyrophilic globular inclusions (Pick bodies) and swollen achromatic neurons (Pick cells). Pick's initial patient with progressive aphasia and behavioral disturbance, and his subsequent patients with frontal lobe dementia and aphasia, underwent anatomical examination only. The histological description came later.2It also became apparent that cases of clinical PiD with frontal and temporal lobe atrophy may not show the typical histological