The use of dermoscopy in distinguishing the histopathological subtypes of basal cell carcinoma: A retrospective, morphological study

Background: The role of dermoscopy in distinguishing the histopathological subtypes of basal cell carcinoma (BCC) is not fully elucidated. Aims: To determine the accuracy of dermoscopy in diagnosing different BCC subtypes. Methods: The dermoscopic features of 102 histopathologically verified BCCs were studied retrospectively. The tumours were classified as superficial (n=33,32.3%), nodular (n=46,45.1%) and aggressive (n=23,22.6%) BCCs by histopathology. Statistical analysis included Cohen’s kappa test, proportion of correlation, measures of diagnostic accuracy, diagnostic odds ratio and the credibility ratio of positive (LR+) and negative (LR−) tests. Results: The highest value in all performed tests was seen in superficial BCCs (kappa 0.85; proportion of correlation 93%; diagnostic accuracy 93.1%), good correlation was noted in nodular BCCs (kappa 0.62, proportion of correlation 80%; diagnostic accuracy 80.4%) but dermoscopic correlation with histopathology was low for aggressive BCCs (kappa 0.13; proportion of correlation 79%; diagnostic accuracy 78.4%). Short, fine telangiectasias (83.3%) showed the greatest importance for the diagnosis of superficial BCCs, blue-grey ovoid nests (61.8%) had the highest diagnostic accuracy in nodular BCCs, while arborising vessels (79.4%) was the most significant dermoscopic feature for the diagnosis of aggressive BCCs. Limitations: This was a retrospective analysis and included only Caucasian patients from a single centre. Conclusion: The highest agreement of dermoscopic features with the histologic type was found in superficial BCCs. We did not find any specific dermoscopic structure that could indicate a diagnosis of aggressive BCC. The presence of relevant dermoscopic features in the evaluated cases was determined by the depth of tumour invasion and not by its histology.