Interobserver agreement on dermoscopic features of small basal cell carcinoma (<5 mm) among low-experience dermoscopists

The basal cell carcinoma (BCC) assessment in dermoscopy is based on the recognition of specific characteristics synthesized and described as classical and non-classical criteria, but which may not necessarily present all at the same time. Consequently, a deep knowledge in detecting the aforementioned dermoscopic criteria is crucial in diagnosis. The aim of the study was to evaluate which criteria are more frequently recognized among a group of low-experienced dermoscopists when confronted with the difficult diagnosis of BCC with a diameter lower than 5 mm. We examined 100 BCC finding that data displays a full agreement only for one classical criterion, the lack of pigmented network (Fleiss' κ = 1), while among other classical criteria only arborizing vessels and ulceration exhibit a good agreement among observers (Fleiss' κ &gt; 0.40). Analyzing non-classical criteria, only blue-whitish veil and blue in-focus dots show a good agreement among low-experience observers (Fleiss' κ &gt; 0.40). It is evident that in small size BCC classic dermoscopic criteria are often substituted by non-classical criteria, which represent the neoplasm's early phase. Thus, it is of importance, especially for low-experience dermoscopists, to analyze even the non-classical criteria in order to obtain a diagnosis of early BCC.