Appearance of malignant melanoma after a non-cutaneous cancer diagnosis.

The aim of this study is to find the associations between malignant melanoma (MM) and other non-cutaneous malignancies and to see whether there are possible correlations between them.We analysed a sample of 1720 patients collected by our melanoma database, to identify patients with both MM and non-cutaneous primary cancer (NCC). The incidence rate (IR) included in our database was calculated as the ratio between the observed patients with NCC and those with MM.A total of 74 patients, with both NCC and MM, were included in our analysis, corresponding to 4.30% of patients with MM present in our melanoma database. After breast cancer (24.3%; IR = 1:4), the most common malignancies were lymphomas (14.8%; IR = 1:4), renal cell carcinoma (13.5%; IR = 1:7), thyroid cancer (9.4%; IR = 1:11), and prostatic carcinoma (8.1%; IR = 1:12), followed by other cancers. Among patients with lymphomas, most patients (72.7%) had a non-Hodgkin lymphoma. Our study shows a high coexistence of multiple malignancies in patients with MM.Although we cannot definitively confirm a true association between non-skin cancers and MM, we believe that there are sufficient links for further investigation in order to identify new aetiological factors and therapeutic targets for these cancers.