Prostatic atrophy (PA) is one of the most frequent mimics of prostatic adenocarcinoma. It occurs almost exclusively in the peripheral zone of the gland and gained importance with the increasing use of needle biopsies for the detection of prostatic carcinoma The etiopathogenesis is unknown, and there is controversy related to the potential of PA as a precancerous lesion. The frequency increases with age. Compressions caused by hyperplastic nodules, inflammation, hormones, nutritional deficiency, or systemic or local ischemia, are all possible factors in the pathogenesis of PA. The peripheral zone of the prostate was step-sectioned and totally embedded from the bodies of 100 consecutively autopsied men more than 40 years of age. The fragments were microscopically studied for presence of PA, latent (histologic) carcinoma, high-grade prostatic intraepithelial neoplasia, local arteriosclerosis, and prostatitis. The prostates were macroscopically examined for the presence of nodular prostatic hyperplasia. The autopsy reports provided information concerning the presence of generalized atherosclerosis and benign or malignant nephrosclerosis. PA was seen in 85 of the 100 prostates examined and histologically was subtyped into simple, hyperplastic, and sclerotic atrophy. In 65 (76.47%) of 85 cases, the histologic subtypes were combined. In 33 (50.76%) of these 65 cases, the three subtypes were seen concomitantly, favoring the hypothesis that they represent a morphologic continuum of only one lesion. Fibrosis of the stroma may or may not be present in simple and hyperplastic atrophy. Hyperplastic atrophy associated with fibrosis of the stroma is the histologic subtype that most frequently mimics adenocarcinoma Sclerotic atrophy always presents fibrosis of the stroma. PA increases with age, and, in our study, ischemia caused by local intense arteriosclerosis seems to be a potential factor for its etiopathogenesis. Because there was no relation to latent (histologic) carcinoma or high-grade prostatic intraepithelial neoplasia, PA is probably not a premalignant lesion.1147-54