Morphological changes in human skin melanoma treated by high-energy pulsed neodymium laser radiation

The neodymium (Nd) laser irradiation has been successfully applied to the treatment of slightly elevated skin melanoma. At the same time the histologic aspects of such a treatment have not been precisely investigated. The aim of this study was to retrace the histological features in human primary cutaneous melanomas after 1060 nm high energy mono pulsed Nd laser treatment in the dynamic healing of the affected tissues.

Histologic analysis of cutaneous melanomas irradiated by Nd laser was carried out. Tissue specimens were taken before and immediately after exposure to laser and 1 hour, and 1, 2 and 3 days after wards. Also the wounds that appeared after the scab fell off and the scars formed following laser irradiation were also the subject of histologic analysis at 2, 4 and 6 months post-treatment.

The Nd laser irradiation caused coagulation necrosis of melanoma, epidermis and dermis with skin appendices and superficial layers of subcutaneous fatty tissue. Foci of laser destruction were characterized by strict locality and efficient separation from the adjacent tissues, by the presence of stasis, thrombosis and coagulation of blood and lymphatic vessels. There was an increase of lymphocytes, macrophages and histiocytes in the area damaged by laser as well as in wounds and scars.

The pulsed Nd laser induces acute photothermal damages of melanoma tissue, which differs from the usual thermal lesions and the most critical difference of the effect of this modality is gain of immunocompetent cells in the affected tissue after laser beam application.