Dr. Robert Riddell

Dr. Robert Riddell graduated from the University of London (St. Bartholomew’s Hospital) in 1967, and trained in GI Pathology at St. Mark’s and St. Bartholomew’s Hospitals in London. He moved to the University of Chicago in 1974 and worked there for 10 years before moving to McMaster University in Hamilton Ontario in 1984, where he was chief of Anatomical Pathology. He moved to Mount Sinai Hospital, Toronto, in 2001.

Dr. Riddell has almost 300 publications which are largely in gastrointestinal pathology, primarily in inflammatory diseases, dysplasia and carcinoma throughout the GI tact.

He has edited or written 6 books, which include the AFIP Tumors of the Intestines, 3rd ed, and the two-volume Gastrointestinal Pathology and its Clinical Implications, the second edition of which was published in 2014. Dr. Riddell directs an annual week-long gastrointestinal pathology course for the ASCP.

In 1983, Dr. Riddell was lead author on the paper defining and grading dysplasia in inflammatory bowel disease, a system that is not only still in use but has been extended to other parts of the gastrointestinal tract.

Dr. Riddell has a longstanding interest in Barrett’s esophagus, its pathogenesis, carcinoma and dysplasia that goes back to the 1980s with papers on dysplasia, carcinoma and its relationship to intestinal metaplasia in Barrett’s esophagus, and regression of Barrett’s by overgrowth of squamous mucosa.

This interest continues to the present, and most recently (2015) he undertook a study with Drs. Elizabeth Montgomery (Johns Hopkins Dept. of Pathology) and Michael Vieth (Bayreuth, Germany) to delineate the specific morphological pathways in which carcinomas in Barrett’s esophagus arise. This should allow better resolution of the problems of dysplasia once the pathways are delineated, allow better identification of the phenotypes of esophageal adenocarcinoma, that should in turn allow better delineation of the molecular pathways involved in each of the subtypes.

Dr. Riddell set up immunohistochemistry at McMaster University, and was Head of Immunopathology at Mount Sinai Hospital from 2001 to 2011. Recent research includes elaborating molecular pathways using double immunohistochemistry.