Diagnostic Accuracy of Magnified Dermoscopy and Reflectance Confocal Microscopy in Assessing Melanocytic Lesions

Abstract

Introduction: Magnified dermoscopy (MD), or optical super-high magnification dermoscopy, is an emerging technique in dermatology.

Objectives: The study aimed to evaluate the distribution of conventional dermoscopy, MD, and reflectance confocal microscopy (RCM) features in dermoscopically equivocal pigmented lesions and to estimate their diagnostic accuracy.

Methods: A retrospective analysis of conventional dermoscopic (20x), MD (400x), and RCM images of dermoscopically equivocal pigmented lesions, diagnosed as either nevi or melanoma, was performed. Distribution of features, sensitivity, and specificity for dermoscopy, MD, RCM, and a combination of these last two with conventional dermoscopy was estimated.

Results: A total of 74 nevi and 20 melanomas were included in the analysis. A positive correlation was observed between seven-point checklist in conventional dermoscopy and the diagnosis of melanoma. With MD, a significant correlation between dots, non-edged papillae, and melanoma was observed, but the technique did not have a significant impact on diagnostic accuracy as compared to traditional dermoscopy. On the other hand, RCM, alone or in combination with traditional dermoscopy, proved to increase diagnostic accuracy, in particular, specificity for melanoma diagnosis.

Conclusions: RCM has a defined role in increasing diagnostic accuracy of doubtful dermoscopic lesions, while the role of MD in clinical practice has yet to be defined, and methodologic standardization as well as a revision of terminology is encouraged to improve the recognition of features.

Figure 1

Pictures of conventional dermoscopy (CD) and magnified dermoscopy (MD) in a nevus and a melanoma. A) CD showing a pigmented lesion with different shades of brown color, irregular network and reticular depigmentation, with a histopathological diagnosis of nevus, and B) corresponding MD showing edged papillae/well-defined network lines (stars). C) CD showing a pigmented brown lesion with irregular network and focal reticular depigmentation, with a histopathological diagnosis of melanoma 0.3 mm Breslow, and D) corresponding MD showing non-edged papillae/ill-defined network lines (asterisks) and dots (arrows).

Figure 2

A) Conventional dermoscopy of a melanoma showing an irregular pigmented network; B) corresponding magnified dermoscopy showing non-edged papillae/ill-defined network lines (asterisks) as well as edged papillae/well-defined network lines (stars); C) corresponding reflectance confocal microscopy (RCM) image at epidermal level showing atypical cells (blue circles) and D) RCM of the same lesion at dermo-epidermal level showing atypical cells (blue circle) and non-edged papillae (blue stars).

Figure 3

Receiver operating characteristic (ROC) curve for dermoscopy, magnified dermoscopy (MD), reflectance confocal microscopy, and the area under the curve (AUC) obtained.