Intraductal carcinoma of the prostate: What we know and what we do not know.

Intraductal carcinoma of the prostate (IDC-P) is a malignant, clonal proliferation of cells growing within the basement membrane-bound structures of the prostate. IDC-P is usually associated with unfavorable clinicopathologic parameters such as large tumor volume, high-grade Gleason score, extra prostatic extension and seminal vesicle invasion. Majority of laboratory and patient data suggest that IDC-P represents intraductal spread of invasive carcinoma, rather than a precursor lesion. Additionally, relationship of IDC-P and adjacent invasive carcinoma has been investigated in a series of molecular studies. The differential diagnosis of IDC-P from other lesions is critical for patient management. In this article, we summarize current literatures regarding what we know about IDC-P, including its pathological morphology, incidence, differential diagnosis, molecular features and clinical significance. In addition, we propose several issues that we currently do not know about IDC-P. Further research is needed to better understand the biological nature of IDC-P.