Malignant melanoma of the head and neck in Scotland: an eight-year analysis of trends in prevalence, distribution and prognosis.

Four hundred and eighteen cases of primary cutaneous malignant melanoma of the head and neck were registered with the Scottish Melanoma Group between 1979 and 1985. Distribution of histogenetic types of melanoma was lentigo maligna melanoma 50 per cent, superficial spreading melanoma 24 per cent, nodular melanoma 20 per cent, unclassifiable 6 per cent. Annual registrations of all types increased over the seven-year period but were less for lentigo maligna melanoma than for the other types. Patients with lentigo maligna melanoma were older, and those with superficial spreading melanoma younger, than the overall average. These two features support the hypothesis that the former may be more closely related to cumulative sunlight exposure than are other histogenetic types of melanoma. The sex ratio (F:M) was 1.7:1 for lentigo maligna melanoma, 1.5:1 for superficial spreading melanoma, but 1:1 for nodular melanoma. All types of melanoma were seen most commonly on the cheek. The proportion of lentigo maligna melanoma on the cheek was significantly greater than nodular melanoma or superficial spreading melanoma. Superficial spreading melanoma was significantly increased in frequency on the neck and scalp, and nodular melanoma on the ear. Melanomas of the scalp were significantly more frequent in male patients than female. The anatomical site distribution of nodular melanoma showed considerable differences between the sexes: nodular melanoma of the ear or neck occurred more commonly in male patients and nodular melanoma of the cheek was significantly more frequent in female patients. Five-year mortality data for head and neck melanoma derived from patients registered between 1979 and 1981 revealed that mortality was greater in male than in female patients, but there was no significant difference in prognosis between the three histogenetic types of melanoma when these were stratified according to tumour thickness.