A 6 year prospective analysis of the diagnosis of malignant melanoma in a pigmented-lesion clinic: even the experts miss malignant melanomas, but not often.

We investigated whether the pigmented-lesion clinic (PLC) run by the Department of Plastic and Reconstructive Surgery at Frenchay Hospital was effective in making and excluding the diagnosis of malignant melanoma, by looking at the pattern of referrals over time, the number of melanomas excised and melanomas in which the diagnosis was delayed or missed. We also investigated whether the PLC was having an effect on the thicknesses of melanomas excised. All 9968 patients attending the PLC between 1 January 1993 and 31 December 1998 were included in the study and 586 malignant melanomas were diagnosed; 24.7% of excisions led to the diagnosis of malignant melanoma. Seven invasive melanomas and two lentigo malignas were missed. There was one histological false negative. The PLC has a sensitivity of 98.5% and specificity of 89.2% for the diagnosis of melanoma; the negative predictive value is 99.9%. The PLC is effective in rapidly making or excluding the diagnosis of malignant melanoma, but has had no effect on the average thickness of melanomas excised over the 6 year study period.