[Dubreuilh melanoma: and epidemiologic and prognostic study]

Lentigo maligna melanoma is a specific histoclinical type of melanoma. We studied the epidemiologic features of lentigo maligna melanoma (Dubreuilh's melanoma) and compared prognosis with other types of melanoma.

A retrospective review of 516 cases of cutaneous melanomas, seen from 1985 to 1997, identified 29 cases of lentigo maligna melanoma. Epidemiologic, clinical and prognostic data were collected using a common scoring system for all patients. The chi-squared test, univariate log rank analysis, Cox multiple regression model for multivariate analysis, and actuarial survival curves were applied.

The 29 cases of lentigo maligna melanoma (16 women, 13 men) accounted for 5.9 p. 100 of all melanomas. Mean age at diagnosis was 73 years compared with 54 years for others melanomas. Predominant localization was head and neck. There was no prior history of nevi compared with 50 p. 100. Mean delay to diagnosis was 4 years versus 1 year. All patients have had an occupation with to sun exposure. Mean tumoral thickness was 2 mm. Survival was the same as for extensive superficial melanomas and better than for nodular melanomas. Multivariate analysis showed that prognosis was not better in case of lentigo maligna melanoma. Tumoral thickness was the main prognosis factor.

Our findings confirmed the specific nature of lentigo maligna melanoma and suggested that sun exposure plays an important role. Multivariate analysis did not show that prognosis was any better in case of lentigo maligna melanoma than in other types of melanoma. The thickness of the tumor must be taken into account as for other melanomas.