Prostate Cancer Grading: An Update.

Recent changes in grading guidelines include the adoption of grade groups, reporting of percentage of pattern 4, reporting of intraductal carcinoma, and presence of cribriform pattern, making pathology reports more prognostically accurate and less confusing. However, pathologists in their daily practice still face challenges related to the subjective nature of identification of cancer growth patterns and difficulties related to tangential sectioning, leading to high intra- and interobserver variability of prostate cancer grades in some cases. Reporting and grading small cancer areas, reporting tertiary Gleason patterns, and precise identification and grading of intraductal carcinoma all remain problematic areas of prostate pathology.