**8. Scleromyxedema**

Scleromyxedema is a chronic idiopathic disorder characterized by papules and lesion of induration with dermal mucin deposition and with an increase of dermal collagen resulting in skin sclerosis. Many patients with scleromyxedema have monoclonal gammopathy, with systemic or lethal manifestations. Scleromyxedema represents a generalized variant that needs to be distinguished from localized lichen myxedematosus (variant without sclerosis and paraproteinemia) [53].

### **8.1 Pathogenesis**

The exact pathogenesis of scleromyxedema is unknown, typically affecting middle-aged adults of both sexes equally. The role of the associated monoclonal gammopathy remains a matter of debate, because, for example, paraprotein levels do not correlate with progression of the disease. But clinical remission of scleromyxedema, during the reduction of paraprotein, that follows after autologous hematopoietic stem cell transplantation was described [53, 54].
