Classification of malignant melanoma and benign skin lesions: implementation of automatic ABCD rule

TLDR

The ABCD rule (asymmetry, border irregularity, colour, dermoscopic structure) is a dermoscopic scoring system that helps dermatologists distinguish melanoma from benign lesions. The study aims to automatically detect ABCD features and classify lesions to enable earlier melanoma detection. Automatic ABCD scoring is achieved by preprocessing with Gabor filters for hair removal and geodesic active contours for lesion boundaries, extracting ABCD attributes using a mix of existing and novel methods, and classifying lesions by the total dermoscopy score. On 200 dermoscopic images (80 melanomas, 120 benign), the algorithm achieved 91.25 % sensitivity and 95.83 % specificity, comparable to human performance (92.8 % sensitivity, 90.3 % specificity), indicating a promising melanoma classifier.

Abstract

The ABCD (asymmetry, border irregularity, colour and dermoscopic structure) rule of dermoscopy is a scoring method used by dermatologists to quantify dermoscopy findings and effectively separate melanoma from benign lesions. Automatic detection of the ABCD features and separation of benign lesions from melanoma could enable earlier detection of melanoma. In this study, automatic ABCD scoring of dermoscopy lesions is implemented. Pre‐processing enables automatic detection of hair using Gabor filters and lesion boundaries using geodesic active contours. Algorithms are implemented to extract the characteristics of ABCD attributes. Methods used here combine existing methods with novel methods to detect colour asymmetry and dermoscopic structures. To classify lesions as melanoma or benign nevus, the total dermoscopy score is calculated. The experimental results, using 200 dermoscopic images, where 80 are malignant melanomas and 120 benign lesions, show that the algorithm achieves 91.25% sensitivity of 91.25 and 95.83% specificity. This is comparable to the 92.8% sensitivity and 90.3% specificity reported for human implementation of the ABCD rule. The experimental results show that the extracted features can be used to build a promising classifier for melanoma detection.