The nuclei are fairly uniform. Rare mitotic figures (arrow) may be seen. Pure prostatic ductal adenocarcinomas are rare. They are more frequently seen as a minor component in approximately 5% of the usual acinar adenocarcinomas. They are more aggressive than usual acinar adenocarcinomas and are now assigned Gleason pattern 4 (Gleason score 4+4=8 in pure ductal adenoca) in the absence of necrosis and pattern 5 if necrosis is present.