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Consumption of the epidermis (COE), defined as thinning of the epidermis with attenuation of basal and suprabasal layers and loss of rete ridges adjacent to collections of melanocytes, is a recently coined term encompassing changes of the epidermal architecture associated with melanoma. To evaluate this feature as an additional diagnostic criterion for melanoma, we examined COE in 453 melanocytic lesions, including 213 invasive melanomas from a population-based series and 240 suspicious pigmented lesions from a clinic-based series, excluding halo and Spitz nevi. In the population-based series, COE was identified in 92/213 (43%) invasive melanomas and became progressively more frequent with increasing Breslow depth (P < 0.0001) and Clark level (P = 0.0002). COE was more frequent when mitotic figures (P < 0.0001), ulceration (P = 0.005), or vertical growth phase (P = 0.009) were present, but it was not significantly associated with age, gender, site, regression, or tumor-infiltrating lymphocytes. In the clinic-based series of pigmented lesions, COE was present in 2/25 (8%) in situ melanomas, 1/29 (3%) lesions classified as melanoma in situ/high-grade dysplastic nevi, and 1/40 (2.5%) high-grade dysplastic nevi. COE was not identified in 146 low-grade dysplastic, congenital, or common nevi. In the combined datasets, 94/96 (98%) lesions exhibiting COE were classified as melanoma. This study demonstrates that COE is frequently present in invasive melanomas, is associated with more aggressive histopathologic features (including increased Breslow depth and ulceration) and may be a useful supplementary diagnostic criterion for melanoma. Furthermore, the process leading to COE may be the first step in a progression to ulceration.

Objective: To describe the diagnostic performance of SolarScan (Polartechnics Ltd, Sydney, Australia), an automated instrument for the diagnosis of primary melanoma., Design: Images from a data set of 2430 lesions (382 were melanomas; median Breslow thickness, 0.36 mm) were divided into a training set and an independent test set at a ratio of approximately 2:1. A diagnostic algorithm (absolute diagnosis of melanoma vs benign lesion and estimated probability of melanoma) was developed and its performance described on the test set. High-quality clinical and dermoscopy images with a detailed patient history for 78 lesions (13 of which were melanomas) from the test set were given to various clinicians to compare their diagnostic accuracy with that of SolarScan., Setting: Seven specialist referral centers and 2 general practice skin cancer clinics from 3 continents. Comparison between clinician diagnosis and SolarScan diagnosis was by 3 dermoscopy experts, 4 dermatologists, 3 trainee dermatologists, and 3 general practitioners., Patients: Images of the melanocytic lesions were obtained from patients who required either excision or digital monitoring to exclude malignancy., Main Outcome Measures: Sensitivity, specificity, the area under the receiver operator characteristic curve, median probability for the diagnosis of melanoma, a direct comparison of SolarScan with diagnoses performed by humans, and interinstrument and intrainstrument reproducibility., Results: The melanocytic-only diagnostic model was highly reproducible in the test set and gave a sensitivity of 91% (95% confidence interval [CI], 86%-96%) and specificity of 68% (95% CI, 64%-72%) for melanoma. SolarScan had comparable or superior sensitivity and specificity (85% vs 65%) compared with those of experts (90% vs 59%), dermatologists (81% vs 60%), trainees (85% vs 36%; P =.06), and general practitioners (62% vs 63%). The intraclass correlation coefficient of intrainstrument repeatability was 0.86 (95% CI, 0.83-0.88), indicating an excellent repeatability. There was no significant interinstrument variation (P = .80)., Conclusions: SolarScan is a robust diagnostic instrument for pigmented or partially pigmented melanocytic lesions of the skin. Preliminary data suggest that its performance is comparable or superior to that of a range of clinician groups. However, these findings should be confirmed in a formal clinical trial.