Dermoscopy of chondrodermatitis nodularis helicis.

Chondrodermatitis nodularis helicis (CNH) is a benign auricular disease whose differentiation with nonpigmented tumors is mandatory. Clinical characteristics of CNH are well known, but there is no information about the dermoscopic features that could help differentiate CNH from squamous cell carcinoma and other non-melanoma skin cancers. To describe the dermoscopic appearance of CNH and to formulate a differential diagnostic model, we conducted  a retrospective, single center, observational dermoscopic study on a sample of 189 biopsy-proven lesions: 25 CNH; 26 squamous cell carcinomas; 62 basal cell carcinomas and 76 other benign and malignant tumors. Univariate and multivariate analyses were conducted by logistic regression. The most significant dermoscopic finding for CNH was a peculiar global configuration (daisy pattern), consisting of white thick lines, radially arranged, converging to a central rounded yellow/brown clod (an erosion covered by keratin or sero-crust). This pattern achieved 92 and 98% of specificity for discriminating CNH with squamous cell carcinoma and basal cell carcinoma, respectively. In conclusion, dermoscopy is valuable for the diagnosis of CNH as a first screening tool because of a consistent global dermoscopic configuration (daisy pattern), consisting of radially arranged white thick lines surrounding a central rounded yellow/brown clod.