By Sharon W. Weiss, MD, Professor and Vice Chair, Director of Anatomic Pathology, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA; and John R. Goldblum, MD, FCAP, FASCP, FACG, Professor of Pathology, Chairman, Department of Anatomic Pathology, Cleveland Clinic Lerner College of Medicine, Cleveland, OH |