Intraductal Carcinoma of the Prostate Diagnosed by Multi-Parametric Prostate Magnetic Resonance Imaging (MRI) and MRI/Ultrasound Fusion-Guided Biopsy

Although, the term “intraductal carcinoma of the prostate” (IDC-P) was first used by Rhamy, McNeak and Yemoto, were the first to delineate IDC-P as a distinct biological entity with definable histological and clinical features. IDC-P is defined as aproliferation of malignant prostate adeno carcinoma cells distending or completely spanning the lumen of pre-existing prostatic ducts and acini, with at least focal preservation of basal cells. Watts et al. estimated the incidence of IDC-P to 2.8% in prostate biopsies.

Histological criteria for the diagnosis of IDC-P include solid; dense cribriform (>50% cellularity of the lumen); trabecular/micropapillary; and loose cribriform intraductal proliferation of malignant cells. The latter two growth patterns share much similarity with HGPIN. In these instances, additional diagnostic criteria, such as marked nuclear pleomorphism (nuclear enlargement > 6x normal nuclei), and nonfocal comedonecrosis (> 1 duct showing comedonecrosis) are criteria needed to differentiate it from HGPIN.