Clinical pathology of sunlight hyperkeratosis.Clinical-pathological examination of sunlight hyperkeratosis 161 lesions in this department.

We have studied 161 lesions of solar keratoses in 67 patients. The peak for age distribution was between 70 and 79 years old. The majority of these cases had SK on the face. The solar keratoses with invasive lesion were in 9 (13%) of 67 patients. By an immunohistochemical study, 15 (50%) of 30 specimens without invasive lesion showed nuclear staining with anti-p53 antibody, while 8 (80%) of 10 specimens with invasive lesion were p53 positive. In the cases with high p53 expression (Labeling index exceeding 30%), there was no difference between SKs with invasive lesion and those without invasive lesion. The MMP-9 positive cells were observed in 5 (50%) of 10 specimens in SK with invasive lesion, suggesting that the expression of this proteinase may be involved in the process of SK invasion.