Possible formation of cutaneous amyloid from degenerative collagen fibers : ultrastructural collagen changes and the immunoreactivity of cutaneous amyloidosis employing anti-type I, III, IV, V collagen antibodies

The origins of primary cutaneous amyloid have been investigated and several possibilities are proposed. We investigated here several cases by electron microscopy and found in all cases characteristic filamentous changes which were identical with amyloid structures in the collagen bundles. These observations suggested a possible pathway of cutaneous amyloid formation from degenerative collagen fibers. Further studies were performed using immunoelectron microscopical and immunohistochemical methods employing a panel of anti-collagen antibodies to examine the reactivity of amyloid to them. Our results were much more suggestive of the collagen origin of this kind of amyloid.