Abstract
A complex spectrum of mixed brain pathologies is common in older people. This clinical pathologic conference case study illustrates the challenges of formulating clinicopathologic correlations in late-onset neurodegenerative diseases featuring cognitive-behavioral syndromes with underlying multiple proteinopathy. Studies on the co-existence and interactions of Alzheimer's disease (AD) with neurodegenerative non-AD pathologies in the aging brain are needed to understand the pathogenesis of neurodegeneration and to support the development of diagnostic biomarkers and therapies.