ABCD method for screening skin cancer
To improve diagnostic accuracy, the ABCD rule of lesion screening is widely used, which is based on asymmetry (A), border (B), color (C), and differential structure (D) measuring. • A total dermatoscopic value (TDV) results from the calculation TDV = A·1,3 + B·0,1 + C·0,5 + D·0,5 • This score contributes to the differentiation between benign and malignant lesions: 1,00 – 4,75 – benign skin lesion 4,75 – 5,45 – suspicious More than 5,45 – melanoma Asymmetry A – Asymmetry of Shape, Structure, and Color. The skin lesion is divided into four regions, and symmetry is inspected across the x or y-axis. If asymmetry is only by one axis, it gives 1 point, and if on both axes, there are 2 points calculated. So for shape, structure, and color, there can be 6 points maximum.