Displacement of dermal solar elastosis in malignant melanoma.

BACKGROUND

Ultraviolet radiation (UVR) is a major environmental causal factor for skin malignancy. In this study, we investigated the morphology of the solar elastosis (SE) band in benign and malignant melanocytic lesions.

METHODS

We measured the SE band in perilesional and lesional skin of 13 melanomas (9 invasive and 4 in situ) and 11 melanocytic nevi (5 usual intradermal nevi, 4 blue nevi and 2 desmoplastic nevi) occurring in sun-exposed areas.

RESULTS

The melanoma and nevus groups had similar age range, gender ratio and anatomic distribution. The mean SE thickness was 0.35 mm in melanomas and 0.29 mm in nevi (p = 0.56), indicating similar UVR exposure. There was a mean downward SE displacement (SED) of 0.43 mm in melanomas and essentially no displacement (-0.02 mm) in nevi (p < 0.005). Tumor cells and inflammatory host response were responsible for SED in melanoma.

CONCLUSIONS

SED may help in the differential diagnosis of melanocytic lesions in sun-exposed areas. In melanoma, the new lesion depresses the pre-existing SE band. Conversely, the long-standing nevus co-exists with the SE band without significant displacement. Evaluation of the SE band may help to differentiate melanoma with chronic sun-induced damage as they have a distinct set of molecular alterations.