[Dermoscopic signs as predictors of non-response to imiquimod treatment in superficial basal cell carcinoma].

Background: To describe the dermoscopic features in superficial basal cell carcinoma that are associated with a poor therapeutic response to imiquimod treatment.
Method: Clinical and dermatoscopic photographs of 56 superficial basal cell carcinomas of different patients were compared retrospectively, assessed in our office for five years and treated with topic 5% imiquimod five days a week for six weeks. The different dermatoscopic signs of the lesions were identified and the association of each of them with the response to treatment was assessed.
Results: A total response to treatment was achieved by 69.5% of the lesions of patients treated with imiquimod. Dermatoscopy of responding lesions showed a higher frequency of lesions with in focus gray dots (43.6%) and multiple erosions of less than 2 mm (61.5%), without observing statistically significant differences. Within the group with poor response to treatment, a greater number of lesions were found with the presence of arborizing telangiectasias (58.8%), blue-gray ovoid nests (41.1%), ulceration (58.8%), shiny white-red structureless areas (82.2%) and chrysalis (41.2%). The areas in blue-white veil areas (23.5%) and rainbow pattern (23.5%) were only observed in non-responding lesions. Both groups were similar regarding age, sex, diameter of lesions and frequency of some dermatoscopic signs: fine short telangiectasias, gray blue globules, arc-leaf areas and cart-wheel structures.
Conclusion: The study identified dermatoscopic criteria that are significantly associated with a worse response to treatment with imiquimod. In contrast, we found no dermatoscopic signs that correlate specifically to a complete response to treatment.