Amyloidosis of the skin: a comparison between localized and systemic amyloidosis.

Skin biopsies from patients with different forms of localized and systemic amyloidoses were studied. Subepidermal deposits, typical of lichen amyloidosus, were also seen in other types of amyloidosis, least frequent in the secondary systemic form. Amyloid within the epidermis and especially the horny layer as well as pigmented cells close to the deposits were found in all cases of lichen amyloidosus but in no other specimens. Plasma cells, on the other hand, were numerous in nodular amyloidosis but were not found in any other cases. It is concluded that in the pathogenesis of lichen amyloidosus the epidermis and perhaps dermal melanocytes are involved. In the pathogenesis of localized nocular amyloidosis the plasma cells might be of importance.