Cutaneous
lasers, including
argon, Q-switched Nd:YAG, Q-switched ruby, Q-switched
alexandrite, and short
pulsed dye lasers, have been used to treat solar
lentigines and other benign melanocytic lesions. However, the effects of these
lasers at standard fluences on atypical melanocytic lesions have not been examined. We describe two patients in whom the Q-switched
ruby laser failed to successfully treat clinically atypical-appearing solar
lentigines. In both, clinically atypical-appearing melanocytic lesions were treated with excellent initial cosmetic results. In the first patient, the pigmentation returned several months
after treatment and continued to increase in size and color. A biopsy specimen 30 months after Q-switched
ruby laser therapy revealed a
lentigo maligna melanoma. In the second patient, the lesion recurred 6 months after Q-switched
ruby laser therapy, and a biopsy specimen 1 year
after treatment showed an early
lentigo maligna. Thus Q-switched
ruby lasers and other cutaneous
lasers capable of targeting
melanin may be inadequate to eliminate
lentigo maligna and other atypical melanocytic lesions completely. These cases emphasize the importance of careful clinical assessment before any
laser surgery and the need to advise patients to return for evaluation should pigmentation return.