We report herein 2 cases of localized cutaneous mucinosis occurring in skin adjacent to joint replacement for osteoarthritis. Although the cause of these cutaneous manifestations is unclear, there may be an association with underlying joint disease and the surgical prostheses.
A 75-year-old white woman presented with lesions located over her knees that began approximately 3 months after bilateral knee replacement for osteoarthritis. Examination revealed mildly erythematous soft papules localized to the extensor surface of her bilateral mid legs (Figure 1). Her medical history was significant for well-controlled hypothyroidism for many years, hypertension, and hypercholesterolemia. Results of a complete blood cell count and serum protein electrophoresis, levels of thyroid-stimulating hormone and free thyroxine, and antinuclear antibody titers were all within normal limits. A punch biopsy specimen revealed increased dermal mucin without increased cellularity or fibrosis (Figure 2). These histologic findings were consistent with a primary mucinosis. Compression therapy was initiated, and at 1-month follow-up the lesions were unchanged. Of note, the prostheses were functioning well at the time of the examination.