This course will focus on diagnostic challenges in prostate needle biopsy interpretation with special emphasis on current developments. Topics to be covered include prostatic intraepithelial neoplasia, "nucleolus-poor" clear cell adenocarcinoma following anti-androgen therapy, and recurrent/residual carcinoma following brachytherapy. Benign mimics of cancer such as atypical adenomatous hyperplasia, atypical basal cell hyperplasia, and post-atropic hyperplasia will also be discussed. Although the emphasis is on common diagnostic problems facing the practicing pathologist on a routine basis, there will be discussion of pathological processes occasionally encountered in the prostate such as neuroendocrine differentiation, carcinosarcoma, adenoid cystic/basal cell carcinoma, and phyllodes tumor. The minimum diagnostic criteria for adenocarcinoma in needle biopsies, value of diagnostic immunohistochemistry, and DNA ploidy as a prognostic marker will be covered. The twelve cases presented will emphasize practical approaches to diagnosis with time for discussion following each case.

Twelve selected cases will be presented. The pre-registration material will include brief case histories and a set of transparencies (approximately 40) illustrating the microscopic features of entities under consideration. Transparencies are employed rather than glass slides because many of these lesions are microscopic and are not retained with serial sectioning, particularly those identified in needle biopsy specimens.

A complete list of cases to be presented follows:

1. High-grade prostatic intraepithelial neoplasia
2. Post-atrophic hyperplasia
3. Atypical adenomatous hyperplasia
4. Atypical small acinar proliferation suspicious for but not diagnostic of malignancy
5. Focal adenocarcinoma (Gleason grade 3+3=6) on needle biopsy
6. Small cell carcinoma of prostate
7. Adenocarcinoma with androgen-deprivation therapy effect
8. Recurrent/residual adenocarcinoma following radioactive seed implantation (brachytherapy)
9. Carcinosarcoma
10. Gleason grade 3+3=6 adenocarcinoma with extra- prostatic extension and positive surgical margins
11. Adenoid cystic/Basal cell carcinoma of prostrate
12. Phyllodes tumor of prostate

Upon completion of this course, participants should be able to recognize important microscopic findings in prostate needle biopsies that mimic adenocarcinoma, and be able to identify treatment-associated changes in prostate cancer. The participants would also become familiar with histological features of some of the uncommon tumors of prostate such as phyllodes tumor and adenoid cystic/basal cell carcinoma.