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Washington University Experience | NEURODEGENERATION | Argyrophilic Grain Disease (AGD) | 7C Case 7 Denouement
Neuro Final Diagnosis: Alzheimer's disease; Argyrophilic grain disease; Arteriolosclerosis, (moderate) with small, remote, infarct in right basal ganglia. ---- Neuro Diagnosis Comment: The presence of tau-positive inclusions in both neurons and glial cells (astrocytes and coiled bodies in oligodendrocytes, also called argyrophilic grains when impregnated with silver salts) in amygdala and entorhinal cortex and associated structures support the diagnosis of argyrophilic grain disease (AGD), stage 3, which accounts for ~5% of all dementia cases. It typically presents as a late-onset dementia and may account for ~12% of demented individuals older than 65. Microscopy of this brain reveals neocortical areas with few to small foci of beta-amyloid plaques, but no neuritic plaques are present. There are few neurofibrillary tangles, largely confined to the medial temporal lobe, consistent with stage II (range: 0, I-VI) in the Braak and Braak staging of tangles and amyloid stage B (range: 0, A-C). These findings are sufficient to meet the neuropathological criteria for the diagnosis of Alzheimer's disease (AD) according to the criteria of Khachaturian, but the absence of neuritic plaques excludes AD according to the criteria of CERAD, and the NIA-Reagan Institute. The relative preservation of the substantia nigra and absence of Lewy bodies excludes Parkinson’s disease. Vascular pathology in the form of atherosclerosis and arteriolosclerosis are also a feature of this brain. In conclusion, the mild cognitive deficits are probably caused by a combination of Alzheimer’s disease and argyrophilic grain disease.
