The following articles represent the first special issue in a new series of special sections or issues entitled “Insights and Controversies in Pathology.” Each special section or issue in this series will consist of a group of articles providing the most current knowledge, recent advances, and areas of controversy for a specific subspecialty field in pathology. Each special section or issue will be organized by 1 or 2 experts in each subspecialty who have invited recognized authorities to contribute articles. The contributors are selected from countries around the world, giving this series a global perspective.

This series has 2 major objectives: (1) to provide a convenient opportunity for staff pathologists to be brought up-to-date regarding recent advances including new diagnoses, new concepts, and the application of new techniques; and (2) to enlighten trainees and junior faculty in the field of pathology about subspecialty topics for which mysteries remain to be investigated. By combining editors and authors from different countries and backgrounds, I also hope to provoke some discussion about recent advances among pathologists located around the globe.

The authors have no relevant financial interest in the products or companies described in this article.

Author notes

Reprints: Helmut H. Popper, MD, Institute of Pathology, Medical University of Graz, Auenbruggerplatz 25, Graz, Styria A-8036, Austria (