Problems in assessing multiple cutaneous melanoma. A review on the accuracy of a population based cancer registry.

Databases with information on malignant tumors are of great value for epidemiologic studies. From the Regional South Swedish Tumour Registry, which is of documented high quality, 24 patients out of 8008 with reported melanoma diagnosis 1973-2003 were reported as having multiple (> or =3) primary, invasive cutaneous malignant melanomas (CMM). Of the 76 tumours identified in these patients, 7 (9%) were found not to be invasive melanomas.