Clinical and prognostic reports from 270 patients with multiple primary melanomas: a 34-year single-institution study

Development of more than one primary melanoma in a sole patient is frequent, accounting for 1.2-8.2% of melanoma patients in most recent series.

Clinical, histological and epidemiological characteristics of 270 multiple primary melanomas patients were reviewed.

Two-hundred and seven patients (76.7%) had two melanomas, whereas in the remaining 63 the number of primary ranged from three to eight; on the whole, 639 multiple primary melanomas were identified. Synchronous melanomas developed more frequently in patients with three or more lesions; median age was significantly lower in the group of patients with more than three melanomas than in the others. Mean Breslow's thickness significantly decreases (P<0.001) from the first (1.77±1.76 mm) to subsequent primaries (0.85±1.25 mm for the second and 0.66±0.48 mm for the third melanoma). Percentage of 'in situ' melanomas was 5.6% as first diagnosis, but increased to 24.8% for the second melanoma; number of nodular melanomas was significantly lower for succeeding diagnosis. AJCC stage at diagnosis showed a statistical prognostic significance, whereas outcome and survival did not depend on the number of primary lesions. Multivariate analysis confirmed the prognostic role of Breslow's thickness, ulceration, gender and patient age, and the better prognosis of patients with multiple melanomas, respect to those with single primary melanoma.

Skin examination and long-term follow-up are mandatory for patients affected by melanoma, with the intent to promptly diagnose not only a disease progression but also possible new primary melanomas.