Review ArticlesIntraductal Carcinoma of the Prostate: A Guide for the Practicing PathologistVarma, Murali FRCPathAuthor Information Department of Cellular Pathology, University Hospital of Wales, Cardiff, UK Chair Working Group on intraductal carcinoma and tumor growth patterns, ISUP (2019) consensus conference on the grading of prostatic carcinoma. M.V. has no funding or conflict of interest to disclose. All figures can be viewed online in color at www.anatomicpathology.com. Reprints: Murali Varma, FRCPath, Department of Cellular Pathology, University Hospital of Wales, Heath Park, Cardiff CF14 4XN, UK (e-mail: [email protected]). Advances In Anatomic Pathology: July 2021 - Volume 28 - Issue 4 - p 276-287 doi: 10.1097/PAP.0000000000000303 Buy Metrics Abstract Intraductal carcinoma of the prostate gland (IDCP) is characterized by an expansile, architecturally, and cytologically atypical proliferation of prostatic epithelial cells within preexisting prostatic ducts and acini. There has been a wider recognition of IDCP by practicing pathologists since its recognition as a separate category in the World Health Organization (WHO) 2016 classification of tumours of the prostate gland. However, there is also a lack of clarity regarding the diagnosis and reporting of IDCP, which has been compounded by divergent expert recommendations regarding the grading of invasive prostate cancers associated with an intraductal component. The International Society of Urological Pathologists (ISUP) recommends that the IDCP component should be incorporated into the Gleason score, while the Genitourinary Pathology Society (GUPS) recommends excluding it when grading prostate cancer. This review seeks to clarify some of these issues and outline a pragmatic approach to reporting IDCP, particularly in needle biopsies. Diagnostic issues and terminology for lesions falling short of IDCP but exceeding that of high-grade prostatic intraepithelial neoplasia are discussed. The management of patients whose prostate biopsies show only IDCP without an associated invasive component is controversial. Some experts recommend radical therapy, while others recommend prompt repeat biopsy. An alternative clinicopathologic approach that takes into consideration the extent, histomorphology, and location (with respect to a radiologic abnormality) of IDCP, as well as radiologic features, is outlined. Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.