DNA-cytophotometry of benign compound and intradermal naevi, Spitz epithelioid naevi and malignant melanomas.

Single cell DNA cytophotometry was used to characterize seven compound, ten intradermal and six Spitz naevi as well as 23 primary cutaneous malignant melanomas. Compound and intradermal naevi were characterized by a smaller nuclear area than both Spitz naevi and malignant melanomas. Tumour ploidy could not be used as a single criterion of malignancy since both diploid and hyperdiploid melanomas were encountered. The very low mean optical density of Spitz naevi served to distinguish these lesions from malignant melanomas.