Malignant melanoma arising in the scar of lupus vulgaris and response to treatment with topical azelaic acid

Summary A patient with in situ malignant melanoma and squamous cell carcinoma arising in the scar of lupus vulgaris is described. Although the development of squamous cell carcinoma is a well recognized complication this is the first report of melanoma arising within the scar of inactive lupus vulgaris. Treatment with topical azelaic acid resulted in considerable histological improvement of the melanoma.