Features and Prognostic Significance of Intraductal Carcinoma of the Prostate

Intraductal carcinoma of the prostate (IDC-P) is an intraglandular/ductal neoplastic growth of glandular epithelial cells characterized by marked abnormality of the glandular architecture and/or cytological atypia that exceeds what is typically seen in high-grade prostatic intraepithelial neoplasia (HPGIN). It has been shown that IDC-P is a strong independent indicator of poor prognosis for prostate carcinoma (PCa). To review the pathological and genetic features, diagnostic criteria and differential diagnosis, and clinical significance of IDC-P. PubMed was searched using keywords including prostate carcinoma, intraductal carcinoma, IDC, histology, diagnostic criteria, and prognosis. The references in relevant articles were also reviewed. IDC-P is a distinct entity with characteristic morphological and genetic features. It is strongly associated with aggressive PCa with high Gleason score/grade groups and large tumor volume, and portends unfavorable clinical outcomes. Morphological diagnostic criteria have been established to distinguish it from other lesions with similar histological features. IDC-P is an uncommon finding in prostate biopsies, and is even rarer as an isolated finding without concomitant PCa. However, patients with isolated IDC-P in biopsy specimens are recommended to have either definitive treatment or immediate repeat biopsy. It is critical to recognize and report IDC-P, especially in prostate biopsies, where the clinical impact of such a diagnosis is greatest. Intraductal carcinoma is a unique form of aggressive prostate cancer. In this report, we review its pathological and genetic features and poor prognostic significance. It is critical for pathologists to recognize and report this lesion in prostate specimens, especially in prostate biopsies for patient management.