Differences in Dermoscopic Images from Nonpolarized Dermoscope and Polarized Dermoscope Influence the Diagnostic Accuracy and Confidence Level: A Pilot Study


Address correspondence and reprint requests to: Ashfaq A. Marghoob, MD, Dermatology Service, Memorial Sloan-Kettering Cancer Center, 160 East 53rd Street, New York, NY 10022, or e-mail: marghooa@mskcc.org


BACKGROUND Studies have demonstrated differences in colors and dermoscopic structures observed with polarized dermoscopes (PDs) and nonpolarized dermoscopes (NPDs).

OBJECTIVE The objective was to evaluate whether diagnosis and diagnostic confidence changes when viewing dermoscopic images from NPDs and PDs.

METHODS A total of 100 dermatologists participated in the study. Twenty-five pigmented lesions were shown in the study, consisting of 7 seborrheic keratoses (SK), 3 basal cell carcinomas, 2 atypical nevi, 5 malignant melanomas (MM), 3 dermatofibromas, 3 blue nevi, and 2 hemangiomas. Two images of each lesion (one NPD and one PD) were included. The McNemar test and paired t-test were used for the statistical analysis.

RESULTS Ninety-one participants completed the study. Significant differences in the diagnoses were observed for the SK, atypical nevus, and MM images. Seventy-five percent and 59% of the final participants correctly diagnosed SK when presented with the NPD and PD images, respectively. For MM, 23 and 34% made the correct diagnoses with the NPD and PD images, respectively.

CONCLUSIONS Viewing lesions with NPD versus PD can affect the diagnosis and diagnostic confidence of physicians that are novices with dermoscopy. Further studies including physicians at different expertise levels and a larger sample of lesions are needed to further explore the differences.