Scleromyxoedema (lichen myxoedematosus) associated with a paraprotein, IgG1 of type kappa

A case of scleromyxoedema (lichen myxoedematosus) associated with an IgG₁, type kappa paraproteinaemia is reported. Culture of bone marrow material demonstrated that this tissue synthesized monoclonal IgG (subclass γ I) with a light chain of type kappa. The culture of a biopsy specimen of the diseased skin demonstrated low-speed IgG synthesis. It is concluded that the bone marrow and pathological skin synthesize a paraprotein with the same characteristics as that in the serum. Microchemical analysis of pathological skin demonstrated an increase in the content of neutral glycoproteins, hyaluronic acid and chondroitin sulphates as well as the presence of heparin and keratan sulphates. It could not be demonstrated that the serum of this patient contained antibody against connective tissue ground substance or other skin constituents.