Macular amyloidosis with patchy filamentous degeneration of collagen islands

Extensive lichen amyloidosus refractory to DMSO

While lichen amyloidosus reportedly may respond to dimethyl sulfoxide (DMSO) application, we present a patient whose lesions were refractory to this agent. This Japanese woman had chronic extensive lichen amyloidosus, mainly on her trunk. Her 10-year history of using nylon towels was the suspected cause. The application of DMSO ointment had no clinical effect, and the amyloid deposits persisted in the histological specimens despite the treatment. The administration of a topical corticosteroid led to gradual clinical improvement.

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 ingestion of amyloid by pinocytosis or phagocytosis. The developed rough endoplasmic reticulum contained much protein and was active in secretion.