Introduction

On behalf of the Italian Society of Surgical Pathology (SIAPEC-IAP) we dedicate the current issue of Pathologica to the memory of Juan Rosai (August 20, 1940 - July 7, 2020), a man and a pathologist whose inval- uable legacy will remain in the memory of all pathologists throughout the world. His personal history is a metaphor of the history of our world across the 20th and 21st centuries: a history of emigration after the sec- ond world war from Poppi, a small village in Tuscany (Italy), to Argentina where he graduated in the School of Medicine at the University of Bue- nos Aires, followed by setting in the United States in St. Louis, Missouri, where he became Professor & Director of Anatomic Pathology at the University of Minnesota. Subsequently, from 1985 to 1991 he became Director of Pathology at Yale University School of Medicine (New Haven, Connecticut) and from 1991 to 1999, served as Professor and Chairman of Pathology at Memorial Sloan-Kettering Cancer Center in New York City. In 2000 Rosai moved back to Italy, first as Chairman of the Depart- ment of Anatomic Pathology at the Istituto Nazionale dei Tumori (Nation- al Cancer Institute) in Milan and from 2005 at the Center for Oncologic Pathology Consultation, Centro Diagnostico Italiano, in Milan. In Italy he continued his consultation and educational activities with several infor- mal meetings with the Italian colleagues at the multiheaded microscope. Juan Rosai’s scientific production spans uncountable fields and has influenced our view of diagnosing many diseases. His textbook called Rosai and Ackerman’s Surgical Pathology is one of his masterpieces: a book which is still on the shelf of most pathologists across the world. The textbook was first published in 1953 by Rosai’s mentor, Dr. Lauren Ackerman, and the new editions were continued by Dr. Rosai, until the tenth edition published in 2011. In the current issue of Pathologica, we publish a series of articles on some of the topics where Juan Rosai played a fundamental role in dis- covery of diseases and defining diagnostic criteria as well as clinical implications. This selection of articles does not cover all the fields of pathology that Rosai investigated in his boundless scientific production, and we apologize for the many topics that have not been covered, as well as for not having among the authors all the colleagues who knew Juan Rosai personally. We hope that this contribution to Juan Rosai memory will help us to fol- low his path, remembering the importance of him being an outstanding pathologist and a special person with deep feelings and warm empathy.