A new approach to the differential diagnosis of human malignant melanomas

In an attempt to improve the diagnosis of melanotic tumors, we have compared the diagnosis obtained by histological examination of 216 skin tumors and their metastases with that obtained by using a conjunction of four techniques: tissue culture, cytoenzymology, in situ electron microscopy and 5-S-cysteinyldopa (5-S-CD) assay. In 46 cases the final diagnosis as determined by one or more of these tests differed from the initial histological diagnosis, but was confirmed by repeat histological examination. We conclude that this method presents a valuable new approach to the differential diagnosis of human malignant melanoma.