Reliability of diagnosis of melanoma in situ.

Early and correct diagnosis of malignant melanoma is of utmost importance to ensure adequate treatment and the best outcome. Prompted by the death of a patient with an apparent metastasising melanoma in situ, we reassessed 104 people with this malignant disorder, whose diagnosis had been histopathologically verified. We did immunohistochemical analysis of cells with the melanocytic marker melan-A/MART-1, and results of this analysis showed that 30 (29%) of 104 patients had invasive melanomas. One patient died of distant metastases, and the tumour recurred in another. Our finding could be relevant for diagnosis and treatment of melanoma in situ.