Answer: “Intraductal Carcinoma” of prostate

Histology: Intraductal carcinoma of the prostate (IDC-P) is defined as malignant epithelial cells filling large acini and prostatic ducts, with preservation of basal cells forming either: (1) solid or dense cribriform
patterns or; (2) loose cribriform or micropapillary patterns with either marked nuclear atypia (nuclear size 6 x normal or larger) or comedonecrosis. More than one pattern can be present. Basal cells can be either observed on regular hematoxylin and eosin stained slides or demonstrated by immunohistochemical stains for high molecular weight cytokeratin and/or p63.

Discussion: In a recent study by Guo et al, following the diagnosis of IDC-P on prostate biopsies, all six patients who were treated by radical prostatectomy had high-grade infiltrating carcinoma with Gleason score 8 or 9 in their prostatectomy specimen. 5/6 cases had non-focal extraprostatic extension of carcinoma. These findings support prior studies indicating that IDC-P represents an advanced stage of tumor progression with intraductal spread of tumor.

Given that IDC-P on prostate biopsies is frequently associated with high-grade cancer and poor prognostic parameters, diagnosis of IDC-P on needle biopsy should prompt therapeutic intervention rather than surveillance or repeat biopsy.

Reference(s):
– Guo CC, Epstein JI.Intraductal carcinoma of the prostate on needle biopsy: Histologic features and clinical significance Mod Pathol. 2006 Dec;19(12):1528-35.

2-Cohen RJ, Wheeler TM, Bonkhoff H, Rubin MA.
– Cohen RJ, Wheeler TM, Bonkhoff H, Rubin MA.
A proposal on the identification, histologic reporting, and implications of intraductal prostatic carcinoma. Arch Pathol Lab Med. 2007 Jul;131(7):1103-9.