Objectives. High-grade prostatic intraepithelial neoplasia (HGPIN) is often considered a premalignant lesion of the prostate. Its incidence ranges from 0.7% to 20% in all prostate biopsies, and patients with HGPIN on initial biopsy are reportedly found to have a higher risk of cancer on subsequent biopsy. The purpose of our study was to determine the incidence of HGPIN in our patients who underwent prostate biopsy and to determine whether a further pathologic subclassification of HGPIN between HGPIN alone and HGPIN with adjacent atypical glands has any prognostic value in predicting the rate of prostate cancer on subsequent prostate biopsy.

Methods. A total of 485 patients who underwent prostate biopsy between January 1998 and October 1999 were included in the study. Each set of slides was reviewed by a single urologic pathologist to determine the presence of HGPIN alone or HGPIN with adjacent atypical glands. If any HGPIN was identified, a repeat biopsy was performed, and the presence of cancer was recorded.

Results. The overall incidence of HGPIN alone and HGPIN with adjacent atypical glands on initial biopsy was 33 (6.8%) of 485. Of these 33 patients, 21 (64%) had HGPIN alone and 12 (36%) had HGPIN with adjacent atypical glands. Three (14%) of 21 patients with HGPIN alone were found to have cancer on subsequent biopsy compared to 9 (75%) of 12 patients with HGPIN with adjacent atypia on initial biopsy. This difference is statistically significant (P <0.005).

Conclusions. The incidence of HGPIN alone in our experience is 4.3% (21 of 485). Patients with HGPIN with adjacent atypical glands suspicious for cancer have a significantly higher incidence of cancer on subsequent biopsy than patients with HGPIN alone.