Abstract Scleromyxedema or lichen myxedematosus is a rare papular mucinosis of chronic and progressive course and unknown etiology. It is commonly associated with monoclonal gammopathy and may show extracutaneous manifestations, affecting the heart, lung, kidney, and nerves.

The diagnosis is based on four criteria:

generalized papular and sclerodermoid lesions; mucin deposition, fibroblast proliferation, and fibrosis in the histopathology; monoclonal gammopathy; and no thyroid disorders. This article reports the case of a scleromyxedema patient with a recent history of acute myocardial infarction and monoclonal gammopathy.