Multiple melanomas associated with diffuse melanocytic dysplasia.

An uncommon form of presentation of melanocytic dysplasia is described in 15 patients with primary cutaneous melanoma and a high incidence of multiple melanomas. This variation in melanocytic dysplasia appears macroscopically to the pathologist and to the clinician as a diffuse mottling or 'freckling' of the widely excised skin around the melanomas. Most patients also were described clinically as having multiple moles in other sites as well as round the melanoma. Histologically, the abnormally pigmented skin of the wider excisions has the features of melanocytic dysplasia, usually of lentiginous type, and this is seen both in continuity with the melanoma and distant from it including the margins of the wider excisions. These patients seem particularly prone to developing additional primary melanomas and therefore recognition of this form of presentation of melanocytic dysplasia may be important in patient management and prophylactic care of their families.