Prostatic intraepithelial neoplasia: significance and management

Prostatic intraepthelial neoplasia (PIN) is a putative premalignant change that bears a morphological similarity to prostatic cancer and shows increased frequency, severity, and extent in patients with prostate cancer. This article discusses the evidence for PIN as a premalignant lesion, reviews the morphology, terminology, appropriate grading system, and diagnostic significance of PIN, as well as describes management recommendations for further evaluation when PIN is diagnosed in prostate resection and biopsy specimens. Clinical management of high-grade PIN found in transurethral resection of the prostate (TURP) or prostate biopsy specimens should include repeat transrectal ultrasound (TRUS) and prostate biopsy for early detection of prevalent coexistent prostate cancer. In cases of high-grade PIN, increased surveillance methods have the potential to decrease morbidity and mortality by early cancer diagnosis.