Fig. 1

Pink circles of varying diameter were superimposed onto eight replicate histologic images of a single duct involved by low nuclear grade, solid pattern DCIS to simulate necrosis representing 10–80% of the duct diameter in 10% increments. The images, labeled only 1–8, were circulated to breast pathologists with the question “which image represents the minimum amount of necrosis required for a diagnosis of comedo necrosis?”