Amelanotic lentigo maligna.

A 68-year-old woman had a pigmented lentigo maligna lesion excised from her left arm. During a seven-year follow-up period, the excision site gradually evolved into a hypopigmented macule with irregular areas of mild erythema. The clinical impression was neurodermatitis, but a biopsy specimen revealed lentigo maligna without melanin pigmentation. To our knowledge, this is the first case of amelanotic lentigo maligna reported in the English literature in which the clinical presentation was dermatitis-like. Our experience suggests that biopsy should be done on all clinically changing sites of treated lentigo maligna, whether the changes are pigmented or not.