Yu'ichi Terao

Macular amyloidosis with patchy filamentous degeneration of collagen islands

Unusual patchy filamentous degeneration of collagen islands, found in a typical case of macular amyloidosis, is described. This phenomenon was found to begin in intact islands scattered among the amyloid islands in the papillary and upper reticular dermis. Since the patches varied in size, they were thought to have grown gradually with time. They were derived from the degeneration of collagen fibrils and demonstrated a tropocollagen‐like structure. Although the small patches preserved some characteristic structures of collagen fibrils or tropocollagen, the large patches showed amyloid‐like filamentous masses surrounding the collagen islands.

High melanosome engulfing activity of cutaneous fibroblasts in macular amyloidosis: an electron microscopic study

Six patients with macular amyloidosis were investigated by electron microscopy and various morphological changes in fibroblasts were identified. Many cells, which seemed to be macrophages by light microscopy, proved to be fibroblasts. The digesting action of fibroblasts was well developed and many melanosomes were taken into the cells making the cells resemble melanophages. The fibroblasts extended long, thin and branched cytoplasmic processes to surround the amyloid mass, and the cells selectively extended these into the narrow spaces between collagen and amyloid. The fibroblast showed highly developed endocytotic activity and probable ingcstion of amyloid by pinocytosis or phagocytosis. The developed rough cndoplasmic reticulum contained much protein and was active in secretion.