[1539] Topographic Relationship of High-Grade PIN with Atrophy and Adenocarcinoma
D Hull, MK Jarmulowicz, J Ma, J Qian, DG Bostwick. Bostwick Laboratories, Glen Allen, VA
Background: Atrophy of the prostatic secretory epithelium is ubiquitous in the adult prostate. Controversy has arisen regarding the putative relationship between atrophy, high-grade prostatic intraepithelial neoplasia (HGPIN), and adenocarcinoma.
Design: The study group consisted of 42 fully-embedded whole-mounted radical prostatectomy specimens from untreated patients. The percentage of each case involved with atrophy was estimated. Foci of HGPIN and adenocarcinoma were demarcated, the zonal location(s) recorded, and volume and pattern of HGPIN and cancer determined. HGPIN or adenocarcinoma was defined as merging when in physical contact directly with atrophy within an acinus, adjacent when HGPIN or cancer and atrophy abutted, near when occurring within 1 mm, and distant when occurring at a distance of more than 1 mm.
Results: The mean area involved by atrophy was 30.5% (range 5%-70%). A total of 375 foci of HGPIN were observed; 356 and 19 foci occurred in the peripheral and transition zones, respectively. Predominant patterns of HGPIN included 233 tufted (62.1%), 101 micropapillary (26.9%), 37 flat (9.9%), and 4 cribriform (1.1%). The mean volume of HGPIN was 0.022 cm3 (range 0.003 
0.4 cm3). Eighty foci (21.3%) of HGPIN merged with atrophy, 24 foci (6.4%) were adjacent to atrophy, 189 (50.4%) foci were near atrophy (within 1 mm), and 82 foci (21.9%) were distant from atrophy. Six of these foci occurred where HGPIN was seen merging with atrophy; 1 focus occurred in atrophy distant from HGPIN or cancer. There was no association between the HGPIN volume and the extent of atrophy (p=0.09), and no association between the pattern of HGPIN and nearest atrophy (P=0.08). Sixty foci (16%) of HGPIN were adjacent to cancer, 76 foci (20.3%) of HGPIN were near cancer, and 239 (63.7%) foci of HGPIN were distant from cancer. Of the foci of adenocarcinoma nearest atrophy, 354 (94.4%) and 21 (5.6%) foci occurred in the peripheral and transition zones, respectively. The mean volume of HGPIN was significantly greater (0.035 cm3, p value 0.0004) when it occurred adjacent to cancer than near or distant to cancer.
Conclusions: High-grade prostatic intraepithelial neoplasia occurred most commonly less than 1 mm from atrophy (50.4%), but the widespread universal presence of atrophy limits the interpretation of the significance of this finding. HGPIN volume was not associated with the atrophy volume. High-grade prostatic intraepithelial neoplasia had significantly greater volume when it occurred adjacent to cancer.
Category: Pathobiology
Tuesday, March 10, 2009 1:00 PM
Poster Session IV # 200, Tuesday Afternoon