Atypical adenomatous hyperplasia of the prostate. Relationship with carcinoma in 217 whole-mount radical prostatectomies.

Abstract

Atypical adenomatous hyperplasia (AAH) of the prostate is a microscopic proliferation of small glands that may be mistaken for adenocarcinoma. The extent and multicentricity of this histopathologic lesion have not been fully defined, and the spatial relationship with carcinoma has not been described in whole-mount surgical specimens. We sought to determine whether the extent and zonal location of AAH is related to prostate cancer by evaluating 217 totally embedded radical prostatectomy specimens with cancer. All but 17 patients had clinically localized cancer, and none had received preoperative therapy. The number of foci and volume of AAH were measured using a grid-counting method; proximity to cancer was recorded as either less than or equal to 2 mm from cancer or greater than 2 mm from cancer. AAH was identified in 23.0% of cases and was more frequent in the transition zone (19.8% of cases) than in the nontransition (peripheral and central) zone (6.0%). It was found within 2 mm of cancer in 34% of cases of AAH, including 30% of cases in the transition zone and 31% cases in the nontrasition zone. The number of foci of AAH in the transition zone was always greater than that in the nontransition zone, regardless of whether it was within 2 mm of cancer or more than 2 mm from cancer. AAH was frequently multicentric (46% of cases), especially in the transition zone (47% of transition zone cases) compared with the nontransition zone (23% of nontransition zone cases). The mean volume of AAH was 0.029 cc (range, 0-1.29 cc) and was much higher in the transition zone than the nontransition zone, regardless of whether it was within 2 mm of cancer or more than 2 mm from cancer. In cases of AAH within 2 mm of cancer, the volume was lower than in cases more than 2 mm from cancer; this was true regardless of zonal location. AAH was more common in older patients and in those with greater prostatic weight, higher prostatic volume, greater percentage of nodular hyperplasia, greater volume of cancer, greater percent of Gleason patterns 4 and 5 cancer, higher volume of prostatic intraepithelial neoplasia, and higher serum prostate-specific antigen level. There was no correlation of number of foci of AAH or volume of AAH with pathologic stage, seminal vesicle invasion, Gleason primary pattern or score, nuclear grade, perineural invasion by tumor, or DNA ploidy. Our results indicate that AAH is usually found iin the transition zone in association with nodular hyperplasia and is often multicentric. The extent and zonal distribution of AAH and carcinoma show a weak but significant association.