A 16-year-old castrated Maltese was presented by its owner with a 6-month history of progressive cognition failure and behavioral changes. Based on a cognition and behavior evaluation and neurologic and blood examinations, cognitive dysfunction syndrome (CDS) was suspected. Magnetic resonance imaging revealed severe brain atrophy and reduced interthalamic adhesion thickness. A histopathologic examination in biopsied brain tissue revealed multifocal accumulation of lipofuscin in the hippocampus. Based on the cognition and behavior evaluation, diagnostic imaging, and histologic findings, the dog was diagnosed as having CDS with lipofuscin accumulation. To our knowledge, this is first case report of canine CDS induced by lipofuscinosis.

Key words: Brain atrophy, Cognitive dysfunction syndrome, Interthalamic adhesion thickness, Lipofuscin