Melanoma after laser therapy of pigmented lesions--circumstances and outcome.

The use of laser therapy in the treatment of pigmented lesions is a controversial issue as it can delay melanoma diagnosis and may negatively impact mortality. Few cases of melanoma after laser therapy have been reported. It is still unknown whether melanoma can be induced by lasers. We discuss the outcomes of twelve patients presenting with melanoma subsequent to previous treatment with laser. In four patients, a skin biopsy was performed before laser treatment. Histology was re-evaluated by a panel of experienced dermatopathologists and analyzed in the context of clinical and photo-optical data. There was evidence for pathological misdiagnosis in two cases. The other two cases initially presented with non-suspicious features before laser treatment and were clearly diagnosed as melanoma thereafter, opening the possibility of melanoma induction by laser treatment. Most patients were female and presented with facial lesions. Three patients have already died of melanoma and two are in stage IV, showing progressive disease with distant metastases. Laser therapy is a common treatment for pigmented lesions, increasing the risk of delayed melanoma diagnosis. This prevents appropriate and timely therapy, and may therefore lead to a fatal outcome. A careful examination of all pigmented lesions using surface microscopy and representative biopsies in combination with a close follow-up is recommended.