Inflammatory features and rete ridge patterns of facial solar lentigo may guide laser treatment.

Relatively little is known about the clinicopathological characteristics of solar lentigo (SL), rendering the choice of laser treatment a clinical challenge. This study compared the clinicohistopathological characteristics of patients with SL on the face with and without conspicuous inflammation. The medical records were evaluated to determine the clinical and histopathological characteristics. Based on the degree of histopathologically observed inflammation, the patients were divided into two groups, those with inflammatory and noninflammatory SL. The demographic characteristics of patients in the inflammatory (n = 62, 62.6%) and noninflammatory groups (n = 37, 37.4%) did not differ significantly. Lesion duration was shorter, and the proportion of patients whose lesions changed within 6 months was higher in the inflammatory than in the noninflammatory group. The mean longest lesion diameter was greater in the inflammatory than in the noninflammatory group. Histopathologically, epidermis was thicker in the inflammatory than in the noninflammatory group. The grade of basal hyperpigmentation was higher in the noninflammatory group, whereas telangiectasia was more frequent in the inflammatory group. The treatment response rate was lower in the inflammatory (7/21, 33.3%) than in the noninflammatory group (8/10, 80.0%). Optimal laser treatment strategies may differ in these two groups.