Lichen Myxedematosus

Abstract

A case of lichen myxedematosus in a 41-year-old male patient was reported. Clinically, the patient had an elevated lichenification plaque from the occipital region down to the nape. Histochemical examination revealed deposition of hyaluronic acid in the upper dermis. Electron microscopically, collagen fibrils and connective tissue cells were surrounded by a network of ruthenium red-positive filaments, at the crossings of which there were large aggregated particles. Since these filamentous structures occured also in the rough endoplasmic reticulum and the vacuoles of fibroblasts, it was thought that the synthesis of hyaluronic acid by fibroblasts may be increased in the involved area of lichen myxedematosus.