Amyloidogenesis in healing wound. Electron microscopic studies of biopsied wounds in macular amyloidosis.

Clinically and histologically typical skin lesions of macular and lichenoid amyloidoses were biopsied. Rebiopsies were performed after 2 to 16 weeks, and the sequence of amyloid reproduction in granulation tissue was followed. Initially, medium electron-dense proteinaceous substance with fine filaments was produced within or in close relation to the rough-surfaced endoplasmic reticulum of fibroblasts and subsequently discharged. Typical amyloid filaments emerged within and in the vicinity of this substance. A significant number of collagen fibrils were admixed in the centers of some amyloid islands. Predominantly amorphous amyloid substance was seen in contact with the basal laminae. No plasma cells were observed in foci of amyloid. Nonepithelialized wounds did not contain amyloid. It was suggested that, in the primary skin amyloidoses, abnormal dermal fibroblasts produce amyloid precursors under the influence of the epidermis.