Morphologic transitions between proliferative inflammatory atrophy and high-grade prostatic intraepithelial neoplasia

Objectives, To validate with an independent study that simple atrophy/posta trophic hyperplastic lesions (proliferative inflammatory atrophy [PIA]) oft en merge directly with high-grade prostatic intraepithelial neoplasia (PIN) . Methods. Using radical prostatectomies (n =14), all high-grade PIN and aden ocarcinoma lesions were identified. We examined the two-dimensional topogra phic relationship between individual high-grade PIN lesions and PIA, betwee n carcinoma lesions and PIA, and between carcinoma lesions and high-grade P IN. To reduce the possibility that high-grade PIN lesions represented intra prostatic dissemination of carcinoma, all specimens contained total carcino ma volumes of less than 0.5 cc. Results. High-grade PIN merged with PIA in 267 (42.5% of high-grade PIN les ions) of 629 lesions, was adjacent in 57 lesions (9%), was near in 233 lesi ons (37%), and was distant from PIA in 72 lesions (11.5%). Carcinoma did no t merge with PIA; it was adjacent in 24 (30.4%) of 79 lesions, was near in 46 lesions (58.2%), and was distant from PIA in 9 lesions (11.4%). Of 79 ca rcinoma lesions, 18 (23%) merged with high-grade PIN, 11 (14%) were adjacen t, 26 (33%) were near, and 24 (30%) were distant from high-grade PIN. Areas of presumed low-grade PIN were often found in association with high-grade PIN and PIA. Conclusions. Morphologic transitions between high-grade PIN and PIA occur f requently. Although the mere topographic relation of the lesions is not def initive proof of a continuum, these results are consistent with a model in which the proliferative epithelium in PIA may progress to PIN and/or adenoc arcinoma. UROLOGY 56: 828-832, 2000. (C) 2000, Elsevier Science Inc.