Dermatoscopic Prediction of Melanoma Thickness Using Latent Trait Analysis and Likelihood Ratios

Abstract

Breslow thickness and Clark level can be used to determine surgical procedures for cutaneous malignant melanoma and patient eligibility for experimental adjuvant therapy. Efforts to predict the thickness of melanomas using dermatoscopy have focused on differences between single dermatoscopic findings. The aim of this study was to develop a method for preoperative identification of melanomas of > or = 1 mm Breslow thickness using the entire range of dermatoscopic findings. Sixty-five melanomas were assessed for the presence of 22 dermatoscopic features. Ten dermatoscopic features showed differences in thick and thin melanomas and were selected for further analysis. A latent trait analysis construct implied that a progression in dermatoscopic features was associated with advancement of melanomas. Early melanomas are characterized by a light brown colour, a pigment network and irregularity or heterogeneity. Gray-blue areas, white scar-like areas and an atypical vascular pattern gradually displace these features. Likelihood ratios were determined for these 6 dermatoscopic findings and an algorithm for calculating the probability of thick malignant melanoma was established.

Seven-point checklist for dermatoscopy: Performance during 10 years of prospective surveillance of patients at increased melanoma risk

“…These observations are sustained by previous publications showing similar results when comparing thin and thick melanomas. [33][34][35][36] In conclusion, the 7-point checklist for dermatoscopy was less sensitive but highly specific in this prospective surveillance study of patients at high risk in comparison with previous retrospective analyses. However, complementary information (eg, derived from anamnestic data or digital dermatoscopy) helped to identify 48 (38%) additional melanomas and, therefore, clearly increased the sensitivity.…”

Preoperative Melanoma Thickness Determination by 20-MHz Sonography and Digital Videomicroscopy in Combination

“…24,36,37 This may influence the aspect of the pigmented skin lesion image and may lead to the identification of melanoma thickness variables different from those previously identified by epiluminescence microscopy. [16][17][18][19] In our cases, thin melanomas differed from thick ones by the presence of surface microscopic features in the center of the lesion. Tumor progression leads to the disappearance of pigment network, globules, and blotches from the center of the lesions, which are replaced by pinkish white areas or by structureless areas frequently surmounted by the grayish polygonal structures constituted by thick horny scales, corresponding to the grayblue areas observable by means of the epiluminescence technique.…”

“…A vascular pattern was detected in faintly pigmented lesions and in the regressive areas especially in thick melanomas, confirming previous observations. 18,19 Our combined diagnostic approach for the identification of melanomas thicker than 1 mm appeared useful for clinical practice: in our series it allowed the distinction of the majority of thick melanomas without misclassification of thin ones. One of the 3 misclassified thick melanomas was a borderline lesion (histologic thickness, 1.1 mm), and the misclassification depended on a slight underestimation of the sonographic thickness (0.91 mm).…”

“…[34][35][36][37] Recently, the possibility of recognizing melanoma progression phases by dermatoscopy has been reported. [16][17][18][19]38 However, this approach too can lead to misclassification of thin melanomas, because specific aspects of thick lesions can also be present in thin ones. 18 Furthermore, the polymorphism of thin melanomas probably accounts for the nonreliability of the ABCD score for dermatoscopy in distinguishing between thick and thin lesions.…”

“…[6][7][8][9][10][11] Clinical variables, such as palpability, have been suggested as criteria to determine melanoma thickness, 12,13 but their reliability was not confirmed. 14,15 Moreover, surface microscopic patterns [16][17][18][19] and scores 20,21 also in association with clinical examination 18 seemed insufficiently reliable for preoperative determination of melanoma thickness.…”