In situ and intraductal epithelial proliferations of prostate: definitions and treatment implications. Part 2: intraductal carcinoma and ductal adenocarcinoma of prostate.

• High-grade prostatic intraepithelial neoplasia (HGPIN) is an intracellular proliferation of ductal epithelial cells. On its own, the presence of HGPIN does not warrant active intervention. • In contrast, intraductal carcinoma of prostate and prostatic ductal adenocarcinoma of prostate are markers of aggressive prostatic adenocarcinoma. • The presence of even small foci of these tumours on biopsy warrants immediate intervention, even in the absence of demonstrable invasive disease. • This second part of the review of in situ epithelial proliferations of the prostate looks at these conditions in more detail.