Usual and unusual histologic patterns of high Gleason score 8 to 10 adenocarcinoma of the prostate in needle biopsy tissue

High Gleason score 8 to 10 adenocarcinoma is the most aggressive and potentially lethal form of prostate cancer. The 2005 International Society of Urological Pathology (ISUP)-modified Gleason grading scheme defines several gland arrangements of high Gleason grade patterns 4 and 5. The aim of this investigation was to quantitate the frequency of the ISUP-defined high Gleason grade patterns in needle biopsy tissue, to determine the common admixtures and to characterize patterns not presented in the 2005 ISUP report. For patients who underwent radical prostatectomy, we analyzed for association of specific high-grade patterns in needle biopsy with extraprostatic extension in radical prostatectomy tissues. A total of 268 prostate needle biopsy cases with Gleason score of 8 to 10 were examined. A mean of 3.6 patterns (range, 1 to 8) were identified per case and only 12% of cases had a pure single pattern. Ill-defined glands with poorly formed lumina (at 57%) and fused microacinar glands (at 53%) comprised the predominant and most frequently admixed patterns. Single cells and single signet ring cells were present in 53% and 31% of cases, respectively. Additional patterns in order of frequency included cords (35%), cribriform glands (25%), sheets of cells (19%), chains (4%), glomeruloid (3%), comedonecrosis (2%), and hypernephromatoid (1 case=0.3%). Gleason score 8 to 10 carcinomas are typically extensive in needle core tissue, with a mean of 4.4 positive cores (range, 1 to 15 cores) per case. Only 14 cases (5%) had high-grade minimal carcinoma measuring