Atypical lentiginous junctional naevi of the elderly and melanoma.

The diagnosis of atypical lentiginous melanocytic naevi in chronic sun-damaged skin is a clinical and pathological challenge. Mottled skin in the elderly is a result of extensive freckling, guttate hypomelanosis, solar lentigines, seborrhoeic keratoses and small dark lentigines. In addition, atypical lentiginous junctional naevi may be seen as isolated lesions and may merge with lesions that are indistinguishable from lentigo maligna. The predominant site distribution of such lesions on the trunk and limbs and the presence of a nested naevoid pattern on biopsy differs from classical lentigo maligna, which develops mainly on the head and neck. Based on case studies combining dermatoscopy with clinical and pathological features, we have found that atypical lentiginous junctional naevi of the elderly may evolve to lentigo maligna and in some cases to small cell (naevoid) melanomas. Such lesions have been previously classified as dysplastic naevi, atypical melanocytic hyperplasia, atypical melanocytic proliferation, atypical lentiginous melanocytic proliferation or premalignant melanosis (McGovern). The current definition of lentigo maligna appears too narrow and the pathway to lentigo maligna in the elderly skin may include a naevoid subset.