The seven features for melanoma: a new dermoscopic algorithm for the diagnosis of malignant melanoma

European Journal of Dermatology. Volume 9, Number 4, 303-8, June 1999, Cas clinique

Author(s) : V. Dal Pozzo, C. Benelli, E. Roscetti, Institute of Dermatologic Sciences, University of Milan, Ospedale Maggiore di Milano IRCCS, via Pace 9, 20122 Milan, Italy.

Summary : The clinical diagnosis of melanoma has a mean sensitivity of 67%, dermoscopy or dermatoscopy is a non invasive technique which improves this sensitivity. Our purpose was to create a simple dermoscopic method for the diagnosis of melanoma useful in daily office practice. For this reason a training set of 218 cutaneous pigmented lesions was used and scored for 16 dermoscopic features: for each feature sensitivity, specificity and statistical significance were evaluated. The results were used to create a simple dermoscopic diagnostic method of only seven dermoscopic features (7FFM). The method was used to evaluate a test set of 713 pigmented skin lesions consecutively observed. The diagnostic dermoscopic method developed gave a sensitivity of 94.6%, a specificity of 85.5% and an efficiency of 87.6%. Our method improves the sensitivity in the diagnosis of melanoma and can be used for the screening of pigmented skin lesions.

Keywords : cutaneous neoplasms, dermoscopy, dermatoscopy, epiluminescence microscopy, melanoma, skin tumors.

Pictures

Figure 1. Irregular pigment network shows broad mesh and varying features in the same lesions, melanoma, level II, thickness 0.23 mm.

Figure 2. Regression-erythema is a white pinkish depigmented area possibly with a few angiectases, melanoma, level II, thickness 0.59 mm.

Figure 3. Unhomogeneity is an asymmetrical or irregular distribution in the lesion of at least two dermoscopic features not necessarily predictive of malignancy. In this lesion globules and a pigment network show an asymmetrical distribution, melanoma, level II, thickness 0.62 mm.

Figure 4. Sharp margin: abrupt cessation of the dermoscopic features at the periphery of the lesion not < 1/4 of the margin, melanoma, level II, thickness 0.42 mm.

Figure 5. Pseudopods: this lesion presents irregularly distributed pseudopods, melanoma, level II, thickness 0.54 mm.

Figure 6. Radial streaming are thin, closely spaced, parallel pigmented streaming irradiating from the rim of the lesion, melanoma, level II, thickness 0.20 mm.

Figure 7. Gray-blue veil: a blue or gray-faded blue area with ill-defined margins, asymmetrically located inside the lesion, melanoma, level II, thickness 0.98 mm.

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