[Study on amyloid deposition in the skin --electron microscopic observation on filamentous degeneration of epidermal cells].

Primary localized cutaneous amyloidosis showed filamentous degeneration of the epidermal keratinocytes. Although the cells retained the cell membrane and desmosomes, the cytoplasm was displaced by ca. 7nm thick wavy filaments (filamentous cell). Then the degenerated cells lost the cell membrane and situated among the keratinocytes (filamentous mass). The same mechanism was occasionally found in some kind of dermatoses. The filamentous masses which dropped into the dermis changed to amyloid in cutaneous amyloidosis. However, the final product in the other dermatosis was not exactly the same to amyloid observed in the primary localized cutaneous amyloidosis. Though the straight filaments were found in the masses, these were mainly composed of amorphous substance.