Prostatectomy of Simultaneous ASAP and PCa not enough material for such a diagnosis. Two foci that were diagnosed as PCa had a total volume of much less than 0.5 cc and a Gleason score of 6, respectively. Those authors pro- posed that ASAP represented clinically insignificant PCa or marginally sampled PCa and that aggressive diagnostic approaches to seek PCa were necessary whenever ASAP is seen on prostate needle biopsy [21]. If a carcinoma is mar- ginally or imperfectly sampled, the microscopic focus might be very small and might contain only a small number of acini [3]. This is certainly a contributory factor to having much difficulty in evaluating specimens. 　Previous studies described the adenocarcinomas found on follow-up biopsy to be of various grades, 18% to 71% had Gleason scores of 5 or 6, and 29% to 82% were PCa with Gleason scores of 7 or more [17,22,23]. Ultimately, ASAP represented ‘a marginally sampled, tangentially sectioned or out-pouching adenocarcinoma’ [24]. 　The Epstein criteria are currently one of the most widely used definitions for clinically insignificant PCa. These are composed of PSA density of 0.15 ng/ml2 or less, Gleason score of 6 or less, fewer than three biopsies with PCa, and up to 50% of cancer involvement in any core. In another study, clinically insignificant cancer was defined as that with an RP tumor volume of less than 0.5 cc, a Gleason score of 6 or less, and organ-confined cancer [25]. van Oort et al reported that the biological behavior of small volume and insignificant PCa was significantly more favorable than that of a general group of patients undergoing RP [26]. For that reason, patients with such insignificant cancer may be appropriate candidates for active surveillance rather than initial radical therapies. But, the plain fact is that the Epstein criteria cannot predict clinically insignificant PCa accurately in some cases and may underestimate the true nature of PCa in 30.5% of Korean patients and 24% of European patients [27,28]. 　In our study, 61% of the patients diagnosed as having PCa had low-grade cancer with a Gleason score of 5 or 6 and 8% of them had intermediate-grade cancer with a Gleason score of 7. In 31% of our patients, the Gleason score could not be evaluated because of multifocal and very small lesions. Also, 39% of the patients diagnosed as having PCa had a tumor volume smaller than 0.5 cc. Together with the aforementioned studies, our data strongly suggest that ASAP represents clinically insignificant PCa or margin- ally sampled PCa. 　Mechanical distortion from the needle biopsy can result in crush artifact of a few atypical glands and obscure cyto- logic detail. Problems with fixation and processing can pre- vent a definite diagnosis because of poor histological fea- tures [3]. We suggest that alteration of cytological features could result from needle-core biopsy, especially in small- volume foci and that these were some of the reasons we did not find significant features in 10 patients even though the RP specimens contained sufficient tissue. 　Matsumoto et al found a 7.7% increase in cancer detec- tion by use of an additional far lateral sextant biopsy in the peripheral zone, and the 12-core biopsy scheme yielded a 401 7.7% to 13.8% increase in cancer detection in a Japanese series [29]. Furthermore, a recent study by Ploussard et al reported that the 21-core extended biopsy improved the di- agnostic yield of 39.1% for ASAP compared with 12-core bi- opsy and cancers were found at the same sample site (71%) and side (100%) by using subsequent 21-core biopsy of pa- tients with an initial diagnosis of ASAP [30]. In another study, it was reported that sampling only the side or sex- tant site with ASAP would have failed to detect cancer in 39% of patients with cancer detected exclusively in other sites [22]. Therefore, our data and the aforementioned studies suggest that aggressive extended sampling will do better to include additional biopsy of the site of ASAP and saturation biopsy. 　Several limitations to our study exist. Because isolated ASAP is not a generally accepted indication of RP, we eval- uated RP specimens with synchronous ASAP with ad- enocarcinoma and could not evaluate RP specimens with isolated ASAP. Therefore, the diagnosis rates of adeno- carcinoma were different between a previous study [11] and ours (100% vs. 78%). But there was no difference be- tween the characteristics of cancer, such as low grade and small volume caner. In addition, only a limited number of patients (46) underwent RP due to synchronous ASAP with PCa. Also, because we did not routinely perform RP in high-risk patients, which was defined as clinical stage T3b or higher disease or PSA greater than 20 ng/ml or a Gleason score of 8 or greater, advanced PCa was excluded from the beginning of our study. The context results in no significant differences in Gleason pattern between PCa on reexamin- ing whole tissue sections from the site of ASAP and PCa on needle prostate biopsy. CONCLUSIONS Although the pathological entities and clinical significance of ASAP on prostate biopsies have been investigated com- prehensively, a few studies have reported associations be- tween ASAP on prostate needle biopsy and adenocarcinoma in whole tissue sections of surgery. The results of our study show that ASAP is most often marginally sampled cancer or clinically insignificant PCa. Therefore, we suggest that aggressive diagnostic approaches like additional biopsy of the site of the ASAP or more extended biopsy be imple- mented as soon as possible if ASAP is diagnosed by prostate needle biopsy. Conflicts of Interest The authors have nothing to disclose. REFERENCES 1. Bostwick DG, Srigley J, Grignon D, Maksem J, Humphrey P, van der Kwast TH, et al. Atypical adenomatous hyperplasia of the prostate: morphologic criteria for its distinction from well-differ- entiated carcinoma. Hum Pathol 1993;24:819-32. 2. Epstein JI, Potter SR. The pathological interpretation and sig- Korean J Urol 2010;51:398-402