Integrating Implicit and Explicit Relational Biases through Graph-Based Multiple Instance Learning: A Case Study in Skin Lesion Diagnosis
This work addresses the insufficient modeling of structural relationships in skin lesion image classification by proposing a dual-level relational fusion framework. At the implicit level, a convolutional masked autoencoder is employed to learn self-supervised inter-patch relationships, while at the explicit level, a graph attention network leverages multiple graph topologies—such as grid and k-nearest neighbor structures—to facilitate message passing. This approach represents the first effort to jointly exploit implicit self-supervised relations and explicit graph-structured priors, thereby enhancing the model’s structural awareness. The method achieves balanced accuracies of 79.27% and 60.67% on the ISIC-2018 and ISIC-2019 datasets, respectively, significantly outperforming both single-relation modeling strategies and baseline approaches.