Cutaneous mucinoses

Cutaneous mucinoses are a heterogeneous group of disorders in which mucin accumulates in the skin or in the follicles. Mucin is a gelatinous substance composed of glycosaminoglycanes, especially hyaluronic acid and dermatan sulfate bound to small quantities of chondoitin sulfate and heparin sulfate. Though the causes of mucinoses remain unknown, they can be divided into distinctive cutaneous (primary) mucinoses, in which mucin deposition is the distinctive histological sign resulting in clinically distinctive lesions, and cutaneous disorders, in which mucin deposition is an epiphenomenon (secondary mucinoses). Histologically, mucin is recognized after special staining techniques using alcian blue and colloidal iron. The microscopic localization of the mucin deposit is used to distinguish between dermal and follicular forms of primary mucinoses and between epidermal, dermal and follicular forms of secondary mucinoses. We present here the clinical and histological features of primary cutaneous mucinoses and an updated classification. The main therapeutic schemas are outlined.