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 [1] 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 [3] 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.