Prostatic intraepithelial neoplasia: a premalignant lesion

Putative premalignant changes in the prostate have been recognized for a number of years. A variety of synonyms have been given to the most commonly described lesion, one characterized by proliferation and dysplasia of the normal two cell layers lining prostatic acini and ductules. Currently, "prostatic intraepithelial neoplasia" (PIN) is the term most commonly used to describe this entity. In this review, the requirements for a premalignant lesion, the reason why PIN fulfills the majority of these requirements, and a detailed description of the morphologic and phenotypic similarities between PIN and carcinoma will be outlined. Finally, the clinical significance of PIN will be reviewed.