[A colorimetric study of pigmented lesions on oral mucosa]

The purpose of this study is to state the clinical and colorimetric features of pigmented lesions on oral mucosa. Among 201 pigmented lesions on oral mucosa, there were 74 melanin pigmentations (36.9%), 72 exogenous pigmentations (35.8%), 28 pigmented nevi (13.9%), and 27 malignant melanomas (13.4%). Melanin pigmentations were found mainly on the gingiva and lip, exogenous pigmentations were on the gingiva, pigmented nevi were found on the buccal mucosa, and malignant melanomas were on the upper gingiva. Thirty-six pigmented lesions were measured by colorimeter, and each lesion was evaluated numerically using the CIE L*a*b* colorimetric system. The statistical significance was confirmed by Tukey's test and a p value <0.05 was assumed as a significant difference. The color distribution of melanin pigmentation and exogenous pigmentation and malignant melanoma were significantly lower than normal mucosa in L*. A statistical significance was found between each pigmented lesion and normal mucosa in a* and b*. Among malignant melanoma and melanin pigmentation or exogenous pigmentation, a statistical significance was found in a* and b*. The color difference between melanin pigmentation and malignant melanoma was significant. The color distribution is thought to be different in each pigmented lesion, and we suggest that it is useful to use colorimetric features to diagnose each pigmented lesion.