Multiple primary melanoma.

From a series of 712 patients with melanoma, 38 patients (5.3%) had more than one primary melanoma. Twenty-four patients had two primaries, 11 patients had three, 2 patients had four, and 1 patient had eight. Twelve patients (32%) had one or more synchronous primaries. Forty-five percent of all multiple primaries were diagnosed within the first year. Microstaging by level and depth was determined prior to treatment and in patients with nonsynchronous primaries, 83% had a subsequent melanoma equal or less advanced than the original. Twenty-six patients with Stage I primaries were skin-tested with DNCB prior to therapy. No significant differences in delayed cutaneous hypersensitivity reactions were found between multiple primary and matched controls with only a single melanoma. Four of 10 patients with multiple primaries treated with adjuvant BCG or BCG-tumor cell vaccine developed subsequent melanomas suggesting that immunotherapy with BCG will not prevent the development of a new primary melanoma. Survival in patients with Stage I and II multiple primary melanomas was improved compared to Stage I and Stage II patients with a single primary. This study suggests that prognosis in multiple primary melanomas is better reflected by the most advanced primary based on microstaging and the presence or absence of regional lymph node metastases than by multiplicity.