Proposal of a new dermoscopic criterion for pigmented basal cell carcinoma: a multicentre retrospective study

Dermoscopy is widely used for the diagnosis of skin cancer and it increases the accuracy of basal cell carcinoma (BCC) detection. BCC dermoscopic criteria have been updated and divided into vascular, pigment-related, and non-vascular/non-pigment-related. Our multicenter retrospective study tested a new dermoscopic pigment-related characteristic to detect pigmented BCC (pBCC) [brown homogeneous blotches (BHB)]. Cases of pBCC were collected from the databases of IDI-IRCCS of Rome and from three Italian private dermatology centers. BHB are confined patches of brown uniform pigmentation without dermoscopic features (net, fat fingers, etc.) or other internal dermoscopic structures, except for occasional vascular ones like arborizing vessels or globules/dots. Melanocytic and non-melanocytic controls were used. We reviewed photos of 270 pigmented lesions (female 145; 51.8%), including 90 histopathologically verified pBCC and 180 control cases (90 melanocytic and 90 non-melanocytic). BHB were found in 61 cases of 90 pBCC patients. The results showed a 67.8 sensitivity, 93.3 specificity, 83.6 positive and 85.3 negative predictive values, posLR 10.2, negLR 0.3, odds ratio 29.4, p<0.001. Our multicentre retrospective analysis suggested the BHB may be a novel dermoscopic pBCC diagnosis criterion.