53-year-old man with rapid cognitive decline - Diagnosis: Kufs' disease (adult neuronal ceroid lipofuscinosis).

Kufs' disease (adult neuronal ceroid lipofuscinosis) is a rare form of neurodegenerative lysosomal storage disease, the genetic basis of which remains obscure. We present a case of a 53-year-old man with a long history of adult onset epilepsy who presented with confusion and amnesia, and subsequently underwent rapidly progressive cognitive decline associated with myoclonic jerks. The clinical diagnosis was Creutzfeldt Jakob disease. However, autopsy brain examination revealed changes of Kufs' disease (Adult onset neuronal ceroid lipofuscinosis, or ANCL, also known as CLN4). No specific gross abnormalities were found but light microscopic examination revealed widespread neuronal ballooning and histochemical staining showed neuronal accumulation of PAS-positive material. Ultrastructural examination demonstrated excessive and abnormal lipopigment lysosomes typical of neuronal ceroid lipofuscinosis. The typical clinical and pathologic features of the Kufs' disease are discussed and the classification of neuronal ceroid lipofuscinosis is reviewed.