Of 1,444 patients with primary cutaneous melanomas, 57 (3.9%) developed more than one. Most had two primary lesions but one had six. Every effort was made to insure that all melanomas were primary tumors. Most patients developed new primary melanomas within five years of the original operation, but an appreciable number developed them many years later.
In the largest group, second and subsequent primary tumors developed in different areas of the body at later times. The subsequent tumors were not diagnosed at an earlier biological stage than the original tumors. Patients with primary cutaneous melanoma should be made aware of increased risk of developing another primary melanoma and physicians should do careful examinations for new primary melanomas as well as for recurrences of the original melanoma.
Beardmore GL, Davis NC. Multiple Primary Cutaneous Melanomas. Arch Dermatol. 1975;111(5):603-609. doi:10.1001/archderm.1975.01630170061008