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.