Interpretation of Prostate Needle Biopsies
Case 13, 14, 15, 16 -
Contemporary Approach to Gleason Grading and Discussion of Other Important Prognostic Markers in the Needle Biopsy Setting (continued)
Rajal Shah and Ming Zhou
Emerging concept of intraductal prostatic carcinoma (IDC-P)|
It has been recognized that some "invasive", Gleason pattern 3-5 prostatic carcinomas actually have
basal cell layers by H&E staining, or more commonly, on immunostains for basal cells. These lesions
were variably labeled as high grade PIN, ductal type prostatic adenocarcinoma in the past. McNeal et al  first raised the possibility that it may represent an aggressive form
of prostatic adenocarcinoma, as it is almost never seen in the absence of an invasive component. If
present, the invasive component is almost always high grade and has large tumor volume. The prognosis of
cancer harboring these basal cell positive cancer glands is worse. The term "intraductal prostatic
carcinoma (IDC-P)" was introduced. The importance of recognizing IDC-P is its association with a poorer
prognosis than otherwise would be attributed to either high grade PIN or Gleason pattern 3 cancer (for
review, see 2).
The diagnosis of IDC-P in prostate biopsy is difficult. Guo et al 
published morphological criteria in prostate biopsy that define IDC-P as malignant epithelial cells
filling large acini and prostatic ducts, with at least partial 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. Reporting of IDC-P
in prostate biopsy deserves special mentioning. If a high grade (Gleason pattern 4 or 5) invasive
component is present with IDC-P, diagnosis of IDC-P seems to be of academic interest. However, when
associated with a Gleason pattern 3 component, IDC-P should be documented and its poor prognostic
significance should be mentioned. One solution could be grading IDC-P component as pattern 4 or 5. If
IDC-P, however, is not associated with an invasive component in prostate biopsy, it is more difficult to
distinguish from cribriform high grade PIN, it is prudent to diagnose it as IDC-P with a comment that
IDC-P is often associated with high grade invasive prostate cancer.
- McNeal, J, and Yemoto, C, Spread of adenocarcinoma within prostatic ducts and acini: morphological and clinical correlations. Am J Surg Pathol, 1996. 20: p.802-14
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. 131(7):1103-9.
Guo, CC, Epstein, JI, Intraductal carcinoma of the prostate on needle biopsy: Histologic features and clinical significance. Mod Pathol. 2006. 19(12):1528-35.