MID-DERMAL ELASTOLYSIS - AN ULTRASTRUCTURAL AND BIOCHEMICAL-STUDY

Mid-dermal elastolysis (MDE) is a particular elastic tissue disorder i n which selective loss of elastic fibres occurs in the mid-dermis. It is clinically characterized by the appearence of fine wrinkling of the epidermis and perifollicular protrusion which gives the skin an aged appearence. It is sometimes associated with an inflammatory event such as urticaria while other cases are regarded as idiopathic. The pathog enesis of MDE is still obscure. Some authors have underlined the role of macrophage activation and others have imputed UV radiation. We repo rt here a typical case of MDE arising after several attacks of solar u rticaria. Electron microscopic and biochemical studies were carried ou t. Ultrastructural examination showed active elastophagocytosis by mac rophages and mast cells, often degranulated, near phagocytosing cells. Biochemical studies demonstrated that fibroblasts derived from lesion al skin of the MDE patient produced high levels of elastase and cathep sin G compared with fibroblasts from a healthy sex- and age-matched co ntrol. Phagocytosis of morphologically normal elastic tissue is a noti ceable characteristic feature of MDE. In our case mast-cell activation and the abnormal synthesis and/or release of fibroblast elastolytic e nzymes seemed to play a role in the pathogenesis of the MDE.