Alzheimer abnormalities of the amygdala with Klüver-Bucy syndrome symptoms: An amygdaloid variant of Alzheimer disease

Background: Neurofibrillary tangles and β-amyloid plaques have been observed in the amygdala in Alzheimer disease. A disproportionate abundance of this abnormality in the amygdala may cause behavioral symptoms similar to Klüver-Bucy syndrome. Objectives: To describe an atypical behavioral presentation of Alzheimer disease and to review the literature on the subject. Design: Case study. Setting: Outpatient specialty clinic. Patient: A 70-year-old man with progressive behavioral symptoms of hyperorality, hypersexuality, hypermetamorphosis, visual agnosia, hyperphagia, and apathy who died at age 77 of asphyxiation on a foreign object. Main Outcome Measures: Clinical symptomatology, brain imaging, and neuropathology. Results: The pathologic diagnosis was Alzheimer disease with abundant tangles and plaques in the lateral amygdala. Conclusions: This case represents a variant of Alzheimer disease with prominent amygdala abnormalities and a Klüver-Bucy phenotype that was misdiagnosed as frontotemporal dementia. Clinical and imaging findings that may aid in accurate diagnosis are reviewed.