Presenile dementia mimicking Pick's disease: an autopsy case of localized amygdala degeneration with character change and emotional disorder.

This report concerns an autopsy case showing localized amygdala degeneration. The patient was a Japanese single woman without hereditary burden who was 58 years old at the time of death. At the age of 55 years, the patient began to feel anxiety, agitation and depressive in mood. At age 58 years, she developed marked character changes and emotional disorders, although disorientation and memory disturbance were slight. We suspected her disease was a variant of presenile dementia, especially Pick's disease, and some neuroradiological examinations disclosed bilateral temporal involvements. We could not make a definitive diagnosis from the clinical findings. She choked to death 3 years after the disease onset. From the neuropathological examinations, the known neurodegenerative diseases causing dementia, including Pick's disease, were excluded and we diagnosed our case as having localized amygdala degeneration. Localized amygdala degeneration itself is very rare. Moreover, in this case, the amygdala degeneration was presumed to be idiopathic, without any apparent cause. To our knowledge, this is the first case of idiopathic localized amygdala degeneration. This case indicates that localized amygdala degeneration can cause presenile dementia, and that character changes and emotional disorders are predominant over memory disturbance and/or disorientation.