Skin Specimen Digitization and Annotation

Skin specimen WSIs that met the inclusion criteria were stained as previously described, digitized using 1 of 3 models of 3D HISTECH digital slide scanners (P100, P250, or P1000; 3D HISTECH, Budapest, Hungary). As images are normalized per pixel and data augmentation applied to offset variation in color values, variation in scanning devices only serves to diversify the Training Set and strengthen the Validation Set. The resulting .mrxs files were annotated by human annotators using the open-source pathology and bioimage analysis software QuPath (v0.1.3.5)⁶⁴ (link) to create ground-truth labels for SL (See “Datasets: training set”), as well as in other downstream processes.