Melanoma in situ (MIS) arising on chronically sun-damaged skin (also known as lentigo maligna) usually presents as a large hyperpigmented patch on the face of elderly patients. While MIS is itself a nonlethal neoplasm, it can develop foci of invasive disease that can carry the same prognostic implications as those associated with any invasive melanoma.1
Recently, Ahmen and Berth-Jones2 reported successfully treating a case of MIS on sun-damaged skin with topical 5% imiquimod cream. Based on the success of Ahmen and Berth-Jones, we treated our patient's large, recurrent MIS with topical imiquimod. We observed a clearance of the MIS. However, our patient's clinical course was complicated by the development of invasive amelanotic melanoma with satellite lesions.