前列腺上皮内瘤变（PIN），可在单个腺泡或小群腺泡中见到的非典型增生。PIN的分化级可高可低。PIN的发现提示前列腺癌可能存在（约半数伴有高分级PIN）。
This is prostatic intraepithelial neoplasia (PIN), a precancerous cellular proliferation found in a single acinus or small group of acini. PIN can be low or high grade (as seen here). The finding of PIN suggests that prostatic adenocarcinoma may also be present (about half the time with high grade PIN).
