The nature of melanoma. A critical review.

The main object of this review was to examine the various histogenetic types of melanoma in order to determine their nature. Nodular melanoma and superficial spreading melanoma differ in the more rapid growth of the former. For tumors of equal depth of invasion in patients of the same sex, the prognoses are similar. Clinical features with prognostic significance are sex, age, and site of the lesion. Women have a decided superiority in survival up to the age of about 50 years when their superiority declines. Survival rates for men also decline after the age of 50 years but to a lesser degree. Melanomas of the extremities have a better prognosis than melanomas of the axial regions. The histological feature of most prognostic significance is depth of invasion (thickness). Ulceration is partly bound to thickness of the lesion, but has an augmentative effect of its own which is related to rate of growth. Thin lesions with or without regression are often associated with metastases. Melanomas arising in Hutchinson's melanotic freckle have a better prognosis than nodular or superficial spreading melanoma but there has not been any series large enough for definitive markers with prognostic significance to be determined. A similar state pertains in palmar, plantar and subungual melanomas. The initial surgical approach in nodular and superficial melanoma should be based upon the thickness of the tumour, site of the tumour, and sex of the patient. The current classification of malignant melanoma is unsatisfactory. Melanoma arising in Hutchinson's melanotic freckle seems to be a distinct entity. Melanomas of other histogenetic types would be best classified according to site.