Clinicopathological analysis of intraductal proliferative lesions of prostate: intraductal carcinoma of prostate, high-grade prostatic intraepithelial neoplasia, and atypical cribriform lesion.

Intraductal carcinoma of the prostate (IDC-P) and high-grade prostatic intraepithelial neoplasia (HGPIN) are two distinct intraductal lesions; the former is usually associated with invasive carcinoma and has an aggressive course while the latter is considered a precancerous lesion. In addition, there are morphologically lesions not well characterized that fall between IDC-P and HGPIN, consequently termed "atypical cribriform lesions (ACLs)." Using whole mount radical prostatectomy specimens, we evaluated the relationship between these intraductal proliferative lesions and clinicopathological parameters. In this study, ACLs were characterized as a loose cribriform intraductal proliferation with greater architectural complexity when compared to HGPIN, but lacking significant nuclear pleomorphism and/or comedonecrosis. Of 901 radical prostatectomies (2006-2012), IDC-P, ACL, and HGPIN were recorded in 155, 22, 436 cases, respectively. Patients with IDC-P showed more aggressive pathologic features when compared to HGPIN. Invasive cancers in patients with ACL had higher Gleason score (P=.00016), larger tumor volume (P=.025), and more advanced pT stage (P=.023) than those with HGPIN. Cases with ACL showed a higher risk of biochemical recurrence than those with HGPIN and a lower risk than those with IDC-P based on log-rank tests (P=.0045 and P=.0069, respectively). In multivariate analysis, the presence of HGPIN was identified as an independent predictor for infrequent biochemical recurrence (P=.0058). We confirmed IDC-P as a marker of adverse pathologic features and clinical aggressiveness. Our results suggest that ACL should be distinguished from HGPIN and these lesions mandate active clinical surveillance.