Long-term outcomes of imiquimod-treated lentigo maligna

Lentigo maligna (LM) may be disfiguring and can progress to LM melanoma. Surgical excision remains the mainstay of treatment, but may result in disfigurement when used for large facial lesions. Topical imiquimod is a nonsurgical alternative although data on its long-term efficacy remain limited.

To assess long-term outcomes of LM treated with imiquimod cream.

We collected data retrospectively for 33 patients treated with imiquimod cream for biopsy-proven LM from 2001 to 2016. Patients initially applied imiquimod once daily, 5 days/week for 6 weeks, aiming to produce a brisk local inflammatory response. If there was no response, the dose was increased to twice daily 7 days/week for 6 weeks and if again there was no response, to twice daily for 10 weeks.

An inflammatory response developed in 29 (88%) of the 33 patients, and of these, 4 patients stopped treatment earlier than planned because they could not tolerate the inflammatory reaction, while 3 patients reported systemic side effects. There was lesion clearance in 21 (72%) of the 29 patients, and they remained clear after a mean follow-up of 4.1 years. Eight failed to clear; in five the lesion was excised, while the remaining three were managed expectantly.

Our results support the use of imiquimod as an alternative to surgery for the treatment of LM in selected cases. With adequate patient preparation, imiquimod is generally tolerated and can achieve excellent cosmetic results. A clinical response is more likely if there is a brisk inflammatory response, and LM will not resolve if there is no inflammatory response.