Foamy spheroid bodies in the substantia nigra. Report of an unusual case with recurrent attacks of peculiar twilight state.

An unusual case of recurrent attacks of peculiar twilight state persisting for 41 years is the subject of this clinicopathological report. During the attacks the patient had depersonalization, showing a stiff face, and the electroencephalogram showed constant 5 Hz diffuse theta waves. The unique and characteristic neuropathological finding were many foamy spheroid bodies (FSB) in the substantia nigra which sometimes contained varying numbers of fine or coarse eosinophilic granules. Ultrastructurally, the FSB contained various small electron-dense granules and/or membranous structures quite different from so-called spheroids (axonal swellings). Bodian staining demonstrated that some FSB were situated within the bundles of the neuronal processes, suggesting that the FSB has originated from the degeneration of the axon and/or dendrites in the substantia nigra.