Introduction: The risk of multiple melanoma is estimated to be between 1 % and 8 %, with the majority of studies being carried out on North American populations. Our objective was to determine the risk and the clinical-pathological features of multiple primary melanoma in a Spanish Mediterranean population.
Material and methods: We performed a retrospective study of the medical records and the database of the Melanoma Unit of Hospital de Bellvitge, Barcelona, Spain, between 1988 and 2005.
Results: We found 25 cases of multiple primary melanoma among 934 patients studied, representing a risk of 2.6 % in our population of melanoma patients. In 50 % of cases, the second melanoma appeared during the first year of follow-up. These subsequent lesions occurred at a different site from the initial lesion in 58 % of cases. In the majority of cases, lesions in a single patient showed similar cytological and architectural features. However, we did observe marked interindividual variability in the histology of multiple primary melanomas.
Conclusion: Although the risk of a second melanoma in our population appears to be lower than in North American populations, it is not negligible. Melanoma patients must therefore be followed up for life, not only for the risk of metastases but also for the risk of a new primary tumor. Complete examination of the skin must be performed at each visit.