Inter-observer variation between pathologists in the classification of cutaneous malignant melanoma in western Australia.

Inter-observer variation between six pathologists in their application of histological classifications during a survey of cutaneous malignant melanoma was analysed using kappa statistics. The highest levels of adjusted agreement were attained for tumour thickness and the presence of ulceration; intermediate levels were achieved on cross-sectional profile, level of invasion, histogenetic type, solar elastosis and the presence of an associated benign melanocytic lesion; agreement on other histological features of melanoma tended to be relatively poor. The problems experienced in the interpretation of these classifications are discussed and suggestions for their improvement are offered.