Repigmentation of gray hairs with lentigo maligna and response to topical imiquimod

Lentigo maligna is a clinical subtype of melanoma that occurs on sun-damaged skin, often grows slowly, and can become quite extensive if left untreated. If biopsy specimens of these tumors do not reveal sufficient melanocytic cell density, they may not be directly identified as malignant, which may also potentially delay treatment. Lentigo maligna tumors have occasionally been noted to have the capacity to invade and repigment gray hairs.1 This phenomenon does suggest it may one day be possible to repigment hair with normal melanocytic cells. Although surgery is the standard of care for treatment of lentigo maligna, for large tumors this can lead to substantial morbidity and may not be appropriate for some patients. A second-line alternative is imiquimod. Current United States Food and Drug Administration approvals for imiquimod 5% cream include treatment of warts, actinic keratosis, and superficial basal cell carcinoma. Off-label use for lentigo maligna has historically been deemed only acceptable as adjuvant therapy, with studies citing recurrence in 25% to 47% of patients.2,3 Recent meta-analyses suggest an approximately 77% histologic and 78% clinical clearance rate, with treatment intensity and dose affecting ultimate results.4 We present the case of an 86-year-old man with an extensive lentigo maligna and hair repigmentation on the scalp, which was successfully treated with topical imiquimod.