Nine cases thought to be "precursors" of malignant melanoma were submitted to 15 histopathologists who have a special interest in melanocytic lesions. The survey revealed that reliable, objective, and repeatable differentiation among benign melanocytic hyperplasias, "precursors," low-risk malignant melanomas, and Spitz's nevi was not achieved. Furthermore, the terminology varied considerably, and some of the same terms were not always used to mean the same things. Clinicians should be aware of the limitations of histopathological interpretations of lesions containing atypical melanocytes. A higher degree of unanimity appears possible when a more simplified and more widely accepted terminology is employed and when differentiating criteria are more clearly established.