Mucinoses

The cutaneous mucinoses are a heterogeneous group of disorders in which an abnormal amount of mucin accumulates in the skin. The etiopathogenesis of cutaneous mucinoses is unknown, although cytokines such as tumor necrosis factor α and β, interleukin-1 and transforming growth factor β and/or polyclonal and monoclonal immunoglobulins and other unidentified factors in the serum of affected patients may induce the synthesis of glycoaminoglycans. The cutaneous mucinoses are divided into two groups: primary cutaneous mucinoses in which the mucin deposit is the main histologic feature resulting in clinically distinctive lesions, and secondary mucinoses in which the mucin deposition is only an additional histologic epiphenomenon. Primary mucinoses can be divided into dermal and follicular mucinoses. The former includes lichen myxedematosus, reticular erythematous mucinosis, scleredema, dysthyroidotic mucinoses (localized (pretibial) and generalized myxedema), papular and nodular mucinosis in connective tissue diseases, self-healing juvenile cutaneous mucinosis, cutaneous focal mucinosis, digital myxoid cyst, while the latter include Pinkus' follicular mucinosis and urticaria-like follicular mucinosis. Associated disorders include paraproteinemia (scleromyxedema, scleredema), diabetes mellitus (scleredema), hyperthyroidism (pretibial myxedema), hypothyroidism (generalized myxedema) and lupus erythematosus, and dermatomyositis or scleroderma (papular and nodular mucinosis in connective tissue diseases). © 2010 Springer Science+Business Media, LLC.