Prospective Study of Ingenol Mebutate for Non-invasive Lentigo Melanoma of the Face

Non-invasive lentigo maligna (LM) is characterized by an in situ proliferation of melanoma cells, limited to the epidermis. It is found most commonly on the head and neck of elderly persons, with a peak incidence in the seventh or eighth decade. If untreated, it may develop into invasive melanoma. The gold standard treatment for LM is surgery using a 5-10 mm margin. However, the lesions can be large, and conventional surgery can be difficult, particularly on the face. Then, there is a need for a topical non-surgical treatment of LM. Ingenol mebutate (IM)/Picato® is able to induce cell apoptosis and an inflammatory reaction in the epidermis and superficial dermis. Thus, the investigators hypothesize that the topical use of Picato® could induce the cure or a prolonged remission of non-invasive LM. Because of the exploratory phase of this study (no case report and no clinical trial at the early phase of designing this study, only one case report at the time of submission of this form) the investigators will conduct an open label study limited to patients who are not eligible to, or who refuse surgical treatment of their LM. The main objective of this study is to determine the proportion of patients with complete response (CR) obtained 2 months after one or two cycles (for patients who did not respond to the first cycle) of topical treatment by IM 150 µg/g for non-invasive LM of the face (head and neck).