A pilot study of treatment of lentigo maligna with 5% imiquimod cream.

BACKGROUND: Lentigo maligna (LM) is an in situ form of malignant melanoma, and surgical excision is often unsatisfactory. Imiquimod cream is an immune response modifier and induces a predominantly T-helper 1 type response.

OBJECTIVES: Assessment of histological and clinical response of surgically resectable LM after treatment with 5% imiquimod cream.

METHODS: Six patients with LM were treated with 5% imiquimod cream daily for 6 weeks. The whole site of the original lesion was then excised. Clinical and histological and appearances were measured using clinical response and histological grading scores.

RESULTS: Complete or almost complete clearance of pigmentation with minimal residual histological evidence of LM was observed in four patients, one patient showed no clinical or histological improvement, and the remaining patient had almost no residual pigmentation clinically after treatment yet histopathological changes remained as severe as before treatment.

CONCLUSIONS: Topical imiquimod cream merits further investigation as a new therapy for LM.