Differentiating seborrheic keratosis from melanoma among lesions exhibiting blue-white veil: A retrospective study.

Background: Differentiating melanoma (MM) from seborrheic keratosis (SK) containing a blue-white veil (BWV) remains challenging.

Objective: Identify dermoscopic features that can improve upon the differentiation between MMs and SKs exhibiting BWV.

Methods: Images from 110 MMs and 121 SKs containing BWV were aggregated, and 91 MMs and 62 SKs from this data set had complete agreement on the presence of BWV according to 3 expert dermoscopists. Independent readers recorded the presence or absence of dermoscopic structures using a web-based data collection instrument. Odds ratios were used to evaluate the association between features and diagnosis, and Fisher's exact test was used to determine the significance of associations.

Results: The combination of milia-like cysts and/or comedo-like openings (MCCO) within the BWV and BWV encompassing the entire lesion occurred in 56% of SKs and 0% of MM. All MMs had at least one MM-specific structure other than BWV or lacked MCCO.

Limitations: Agreement on dermoscopic feature prevalence was variable. The subset of lesions with complete agreement on the presence of BWV may not be representative of lesions encountered in an individual clinician's practice.

Conclusion: Lesions exhibiting BWV with MCCO and no additional MM-specific features suggest a benign diagnosis, as was not seen in any cases of MM.