[860] Glomeruloid Structures in Needle Prostatic Biopsies: Should They Be Assigned a Grade or Rather Just Grade the Surrounding Tumor?

MM Quintal, A Billis, L Meirelles, LLL Freitas, AGE Duarte, CAM Silva, MAM Bisson, LA Magna. School of Medicine, University of Campinas (Unicamp), Campinas, Brazil

Background: The grading of glomeruloid structures (GS) is controversial. Some urological pathologists do not assign a grade to this pattern and just grade the surrounding tumor. Other experts in the field feel that all GS should be assigned a Gleason pattern 4. We studied the frequency and clinicopathological features of this lesion when present in prostatic needle biopsies (NB).
Design: The study was based on 264 NB and the correspondent radical prostatectomies (RP). Several clinicopathological variables were studied. Tumor extent in whole-mount processed RP was evaluated with a point-count semiquantitative method. Biochemical (PSA) progression was defined as PSA 0.2ng/mL. The data were analyzed using the Mann-Whitney test for comparison of independent samples and Fisher's exact test for comparing proportions. Time to progression-free outcome was studied using the Kaplan-Meier product-limit analysis; the comparison between the groups was done using the log-rank test.
Results: The frequency of NB showing GS was 28/264 (10.6%). From the 28 biopsies with this feature 9/28 (32.1%) biopsies showed low-grade surrounding tumor and 19/28 (67.9%) high-grade. Comparing patients without and with this feature in the needle biopsy for several clinicopathological variables, the findings were, respectively: mean age 62.9 yr and 65.6 yr (p=0.06); clinical stage T2 53.6% and 71.4% (p=0.11); mean preoperative PSA 9.6ng/mL and 9.7ng/mL (p=0.18); mean prostate weight 39.8g and 39.4g (p=0.78); positive surgical margins 42.3% and 57.1% (p=0.16); extraprostatic extension (pT3a) 24.7% and 32.1% (p=0.37); seminal vesicle invasion (pT3b) 11% and 21.4% (p=0.13); and tumor extent 34.2 positive points and 44.5 positive points (p=0.07). At 5 years, the PSA progression-free survival rates were 64% and 58% for patients without and with glomeruloid structures (log-rank, p=0.26).
Conclusions: The frequency of glomeruloid structures in needle biopsies is 10%. This feature is associated more frequently with Gleason high-grade surrounding tumor, however, the presence of this architectural pattern is not associated to any other adverse clinicopathologic finding. The result of this study seems that glomeruloid feature per se should not interfere in the grading of a tumor.
Category: Genitourinary (including renal tumors)

Tuesday, March 10, 2009 1:00 PM

Poster Session IV # 127, Tuesday Afternoon