Attributes and survival patterns of multiple primary cutaneous malignant melanoma.

From a series of 1495 patients with primary cutaneous malignant melanoma (PCMM), 26 patients (1.73%) had multiple primary cutaneous malignant melanoma (MPCMM). This report describes the attributes and survival patterns in this small, but important, subgroup of patients with PCMM. Of 26 patients, 23 had two primaries, two had three primaries, and one had six primaries. Five patients had synchronous and 21 patients had metachronous MPCMM. The median interval between the occurrence of the first and subsequent PCMM in these patients was 1.93 years. The estimated 5-year survival rate from the first melanoma was 83.5%; that from the last melanoma was 53.1%. In summary, MPCMM is a distinct biologic phenomenon. A second or subsequent malignant melanoma should be treated like a primary melanoma.