Intraductal carcinoma of prostate: a comprehensive and concise review

Abstract

Intraductal carcinoma of the prostate (IDC-P) is defined as a proliferation of prostate adenocarcinoma cells distending and spanning the lumen of pre-existing benign prostatic ducts and acini, with at least focal preservation of basal cells. Studies demonstrate that IDC-P is strongly associated with high-grade (Gleason grades 4/5), large-volume invasive prostate cancers. In addition, recent genetic studies indicate that IDC-P represents intraductal spread of invasive carcinoma, rather than a precursor lesion. Some of the architectural patterns in IDC-P exhibit architectural overlap with one of the main differential diagnoses, high-grade prostatic intraepithelial neoplasia (HGPIN). In these instances, additional diagnostic criteria for IDC-P, including marked nuclear pleomorphism, non-focal comedonecrosis (>1 duct showing comedonecrosis), markedly distended normal ducts/acini, positive nuclear staining for ERG, and cytoplasmic loss of PTEN by immunohistochemistry, can help make the distinction. This distinction between IDC-P and HGPIN is of critical importance because IDC-P has an almost constant association with invasive carcinoma and has negative clinical implications, including shorter relapse-free survival, early biochemical relapse, and metastatic failure rate after radiotherapy. Therefore, IDC-P should be reported in prostate biopsies and radical prostatectomies, regardless of the presence of an invasive component. This article will review the history, diagnostic criteria, molecular genetics, and clinical significance of IDC-P.

Keywords: Intraductal carcinoma of the prostate; Neoplasms; Prostate.

Fig. 1

Morphologic subtypes of intraductal carcinoma of the prostate. Low power view of a prostate needle core biopsy showing expansion of the normal architecture by cytologically malignant cells that span the entire lumen (A). The micropapillary/trabecular subtype (B) and cribriform subtypes (C) are demonstrated here.

Fig. 2

Additional morphologic subtypes of intraductal carcinoma of the prostate. (A, B) Sections show a both cribriform and focal solid architecture.

Fig. 3

Intraductal carcinoma of the prostate showing expansion of the normal prostatic duct and acinar structures and complete spanning of the lumen with cytologically malignant cells with preservation of basal cells (p63 immunostain).

Fig. 4

Proposed diagnostic algorithm for atypical cribriform lesions of the prostate. IDC-P, intraductal carcinoma of the prostate; HGPIN, high-grade prostatic intraepithelial neoplasia; PCa, prostatic carcinoma. Reproduced from Shah and Zhou, Adv Anat Pathol 2012; 19: 270-8, with permission from Wolters Kluwer/Lippincott Williams & Wilkins.

Fig. 5

ERG immunohistochemical staining in intraductal carcinoma of the prostate shows strong nuclear positivity. Adjacent cancer acini are also positive. Note the vascular endothelial cells are strongly positive (head arrow), and stromal lymphocytes are weakly positive (arrow), for ERG immunostain.

Fig. 6

High-grade prostatic intraepithelial neoplasia (HGPIN) composed of tall, columnar cells with uniform atypia in a tufted to micropapillary pattern. Micropapillary and cribriform HGPIN can overlap histologically with intraductal carcinoma of the prostate.

Fig. 7

Intraductal spread of urothelial carcinoma consisting of highly pleomorphic urothelial cells with focal areas of comedo-type necrosis.

Fig. 8

Prostate duct carcinoma composed of tall, pseudostratified columnar cells forming occasional true papillary structures. In contrast to intraductal carcinoma of the prostate, basal cells are typically absent.