Treatment of lentigo maligna with imiquimod before staged excision

Imiquimod 5% cream has demonstrated effectiveness in the treatment of lentigo maligna (LM) in several small studies. None of the studies to date have included posttreatment surgical removal to confirm negative histologic margins.

The aim of this retrospective analysis was to assess the efficacy of topical imiquimod in LM by circumferentially examining vertically oriented sections from a geometrically designed "picture frame" margin as well as bread-loafed sections of the central portion after staged excisions of imiquimod-treated lesions of LM.

Forty patients with biopsy-confirmed LM were treated five times a week for 3 months with 5% imiquimod cream before staged excision. Tazarotene 0.1% gel was added when no clinical signs of erythema developed with imiquimod alone after 1 month (10 patients). After the course of topical therapy, patients were assessed for clinical and complete histologic clearance after staged excision.

A total of 33 of 40 patients had a complete clinical response as determined by the absence of remaining clinical lesion on physical examination. Upon histologic review, 30 of 40 patients had no evidence of LM whereas 10 of 40 harbored residual disease. One patient was found to have histologic evidence of invasion after completing the topical protocol. After a mean follow-up of 18 months (range, 12-34 months) and after complete surgical excision of the treatment site, none of the imiquimod-treated patients had evidence of recurrence.

Imiquimod appears to be an effective adjunctive treatment for LM but does not qualify as a replacement therapy for surgery.