Atypical psychosis with disseminated subpial demyelination.

A 34-year-old woman experienced three episodes of an atypical psychosis, characterized by confusion, agitation, delusional thinking, paranoid ideation, and auditory hallucinations, during the 14 months prior to her death. Findings of gross examination of the brain and spinal cord were unremarkable. Histologic examination revealed scattered subpial foci of demyelination throughout the brain stem, with involvement of the hippocampal formation bilaterally. Although occasional active lesions at early stages of development were noted, most lesions were gliotic and therefore quiescent. This case and one similar example of disseminated subpial demyelination found in the literature probably represent an unusual variant of multiple sclerosis.