This 43-year-old woman developed papules and induration of the skin in the upper half of her body 15 years ago. It was asymptomatic until the recent onset of decreased range of motion in her hands and face. Laboratory studies revealed paraproteinemia. This patient is a great clinical example of scleromyxedema. Histopathology was not typical for well-developed scleromyxedema, but shows how difficult diagnosis can be early in the course of the disease. This case had only focal increase in dermal cellularity and a mild increase in interstitial dermal mucin, similar to findings seen in scleredema. Well-developed lesions show spindle cell proliferation ("fibroblast-like" or "fibrocyte") with an increase in dermal mucin. The differential diagnosis of well-developed lesions is nephrogenic fibrosing dermopathy and cutaneous mucinoses.
Histologic sections of skin show an expanded dermis with thickened collagen bundles and increased intercollagenous space.