An archive autopsy case of a 50-year-old man who died of Hodgkin's lymphoma had a 4-year, 4-month history of dementia. After radiochemotherapy, the lymphoma subsided except for involvement of the spleen, but the dementia remained. Neuropathological examination revealed that the pathology was confined to the hippocampus, both hippocampi showing sclerosis without inflammation. Neurons of sector cornu ammonis (CA) 1 were completely lost whereas moderate neuron loss was also observed in sectors CA3 and 4, and the dentate gyrus. Neurons of sector CA2 were relatively well preserved and the subiculum was intact. There was no evidence of global hypoxia, or of neurodegenerative disorders with pathological changes affecting the hippocampus. Although there was a long preneoplastic history, and no inflammatory changes were found at autopsy, the present case of hippocampal sclerosis could be included in the category of paraneoplastic limbic encephalitis associated with Hodgkin's lymphoma or the Ophelia syndrome.