Nodular bilateral amygdala degeneration in demented individuals

Abstract

Among more than 2050 brains in our Alzheimer disease brain banks we came across three brains with well demarcated indurated white-yellow nodules in the amygdalas. Microscopically, these nodules were composed of numerous lipid-laden macrophages located in the central region surrounded by an eosinophilic hyaline-like material with minimal reactive gliosis in the periphery. Neurons within these lesions had a normal appearance but were moderately decreased in number. Beta-amyloid, tau and alpha-synuclein immunostaining revealed no abnormal deposits within the nodules. The three patients had long histories of dementia (one linked to a presenilin-1 mutation). The neuropathological diagnoses were Alzheimer disease in two of them and an unclassified tauopathy with argyrophilic grains in the third.