Objective To develop a standardized histopathological classification system for chronic prostatitis (standardized description of prostatic inflammatory infiltrates) based on a literature review, extensive prospective evaluations in two recognized prostatitis research centres and widespread consensus of international urological centres identified as having major expertise or interest in chronic prostatitis.
Methods Relevant articles for review were identified by a Medline search undertaken by the Cochrane Review Group in Prostate Diseases and Urologic Malignancies, and cross-checking bibliographies of retrieved studies, reviews, book chapters and abstracts of the American Urological Association and International Prostatitis Collaborative Network Annual Meetings. Initial drafts were based on classification systems independently developed by the Prostatitis Research Centers at Queen's University in Canada and University of Washington in the USA. A collaborative draft was distributed to 20 urological/pathological clinical centres who participated in the North American Chronic Prostatitis Collaborative Research Network and First International Prostatitis Collaborative Network. A consensus classification system was then distributed to the participating panel for acceptance.
Results The literature review identified a reasonably consistent description of inflammatory infiltrate locations and patterns that were further incorporated into the draft based on the Queen's University and University of Washington proposals. Eighteen (90%) of the identified Prostatitis Centers participated in the revision of the draft and the final consensus process. The final consensus document classifies prostatic inflammation according to its extent and grade/severity in each tissue compartment (location).
Conclusion The consensus of the expert panel was that this classification system can be used in the evaluation of prostatic inflammation in prostate biopsies, transurethral resected prostate chips or prostatectomy specimens. A standardized accepted framework to describe histopathological prostate inflammation will prove useful in evaluating prostate disease.