One of the most relevant diagnostic methods used in dermatoscopy is the ABCD rule (A, asymmetry; B, borders; C, colors; D, differential structures) set forth by Stolz et al.1 Nachbar et al2 demonstrated the reproducibility of the ABCD rule in a prospective study, with 90% specificity and 93% sensitivity in the diagnosis of melanoma. However, 2 recent studies revealed controversial results regarding the validity of the ABCD rule.3,4 To investigate interobserver reliability and diagnostic validity of the ABCD rule in the diagnosis of melanoma, 129 small (≤5-mm) melanocytic skin lesions were evaluated by 6 observers in a retrospective study.
Pizzichetta MA, Talamini R, Piccolo D, Argenziano G, Pagnanelli G, Burgdorf T, Lombardi D, Trevisan G, Veronesi A, Carbone A, Soyer HP. The ABCD Rule of Dermatoscopy Does Not Apply to Small Melanocytic Skin Lesions. Arch Dermatol. 2001;137(10):1376-1378. doi: