Most studies on the risk of cancer after high-grade prostatic intraepithelial neoplasia (PIN) on biopsy have been small (fewer than 100 men), have not analyzed in detail if histologic features can predict cancer, and have not assessed the risk of cancer with multiple repeat biopsies. We analyzed 245 men in whom the only abnormal finding on the initial biopsy was high-grade PIN and who had at least one follow-up biopsy. Repeat biopsy identified cancer in 32.2% of men. If only one follow-up biopsy had been performed on the 245 men, only 24.5% of men would have been found to have cancer. The only independent histologic predictor of a cancer diagnosis was the number of cores with high-grade PIN; risk of cancer: 30.2% with 1 or 2 cores, 40% with 3 cores, and 75% with >3 cores. The following did not predict cancer: number of high-grade PIN glands, maximum percentage of gland involved by high-grade PIN, nucleolar prominence, percentage of cells with prominent nucleoli, pattern of high-grade PIN (flat, tufting, micropapillary, cribriform), marked pleomorphism, digital rectal examination, transrectal ultrasound findings, family history of prostate cancer, serum prostate specific antigen (PSA) at time of high-grade PIN diagnosis, and rate of change of serum PSA. Eighty-one (33%) men had more than one follow-up biopsy; in these cases the following findings on the original high-grade PIN biopsy predicted cancer: the presence of mitoses, the number of positive cores, predominant micropapillary and cribriform high-grade PIN, and very large prominent nucleoli. Of 81 men with more than one follow-up biopsy, if the first repeat biopsy were benign, high-grade PIN, or atypical, the eventual cancer rate was 10%, 25.9%, and 57.1%, respectively (p = 0.002). Of 15 men with more than two repeat biopsies, only two (13.3%) had cancer. In summary, approximately one third of men with high-grade PIN on biopsy have cancer on follow-up. If cancer is not found on the first two follow-up biopsies, it will unlikely be found. Although clinical findings at the time of diagnosis of high-grade PIN are not useful to predict who might have cancer, histologic findings may help identify who needs additional biopsies.

No abstract

Atypical cribriform lesions on prostate needle biopsy specimens are rare and difficult to diagnose. Of 574 high-grade prostatic intraepithelial neoplasia (PIN) lesions on needle biopsy seen at our institution over 75 months, we identified 23 consult cases in which the differential diagnosis was cribriform high-grade PIN versus infiltrating cribriform carcinoma. Prebiopsy prostate-specific antigen (PSA) averaged 6.5 ng/mL (range, 0.3 to 37.3). A positive digital rectal examination (DRE) was present in 12 of 22 (55%) patients for whom information was available. Ordinary high-grade PIN was present elsewhere in the biopsy specimens in 32% of cases. The following architectural features of cribriform glands were evaluated: number (mean, 5; range, 1 to 21); largest size (mean, 0.5 mm; range, 0.1 to 1 mm); necrosis (14%); detached cribriform fragments (18%); stromal fibrosis (18%); and bilaterality (22%). Cytologically, there was cellular maturation toward the center of the cribriform glands (45%); identifiable basal cells on hematoxylin and eosin sections (36%); marked nuclear atypia (9%); and mitoses (23%). Nucleoli were not visible in 18% of cases, small in 36%, and prominent in 45%. With a mean follow-up of 13.8 months for those without progression (25.9 months' overall follow-up), a repeat biopsy diagnosis of cancer was seen in 10 of 22 men [by report: Gleason score (Gs) 4 (n = 1); Gs 6 (n = 3); Gs 7 (n = 4); Gs 9 (n = 2); three biopsy specimens showed ductal features]. An additional two men developed bone metastases without biopsy. Overall, 12 of 22 (55%) patients had cancer on follow-up (one patient lost to follow-up). Four clinicopathologic findings predicted carcinoma on follow-up: positive DRE (p = 0.02); positive transrectal ultrasound (p = 0.02); bilateral atypical cribriform glands (p = 0.02); and detached cribriform glands (p = 0.04).