| Abstract: | A case of the hyperkeratotic type of macular amyloidosis was electron microscopically examined using the refixation-reembedding method. All the cytoid bodies seen in the dermis were amyloid islets associated with malformed basal lamina-like material. The uppermost amyloid islets were in close apposition to the basal cells, which had neither hemidesmosomes nor intact basal lamina. Anchoring fibril-like filaments were seen between the amyloid islets and the basal lamina-like material. Many fibrillar bodies and clusters were present in the spinous layer, but not in the dermis. Masses of eosinophilic, PAS-positive ovoid bodies seen in the horny layer were tightly packed fibrillar bodies shifted from the spinous layer to the horny layer. These findings suggest that the disturbed basal cells produce an amyloid substance in the dermis, as well as malformed basal lamina. The colloid bodies formed by the degeneration of the basal cells seemed to shift up to the horny layer but not to contribute to the amyloidogenesis in this case. |
