Occurrence of cutaneous and uveal melanoma in patients with uveal melanoma and their first degree relatives.

Uveal and cutaneous melanomas are rare tumours, but have been described to occur together in one patient or in members of the same family. A group of 109 consecutive uveal melanoma patients from one specialized ocular tumour clinic were investigated dermatologically. The patient's own history and medical data and the family history of skin or eye problems were recorded. A total of three cutaneous melanomas were found as a result of this study--two in ocular melanoma patients and one in a first-degree relative. Four patients had first-degree relatives with a skin melanoma (in three of these families dysplastic naevus syndrome was also found), and one patient had a first-degree relative with an uveal melanoma. To find cutaneous and uveal melanoma coexisting in two cases and cutaneous melanoma in first-degree relatives in four cases out of a total of 109 uveal melanoma patients seems more than a coincidence. A linking factor in three cases was the familial atypical multiple mole melanoma syndrome, suggesting a common genetic predisposition to both malignancies in these families. In our only family with familial uveal melanoma, cutaneous melanoma and atypical naevi did not occur. A different genetic mechanism for these cases is probable.