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.