The Origin and Development of Benign Prostatic Hyperplasia An Age‐Dependent Process

Although the exact cause of benign prostatic hyperplasia (BPH) is not well defined, it is thought to occur as the result of epithelial-stromal interactions in the appropriate hormonal milieu. Benign prostatic hyperplasia originates in the periurethral and transition zones of the prostate in a microscopic (histologically identifiable) state as early as the third decade of life. With advancing age and the presence of androgens, approximately 50% of microscopic BPH will develop into macroscopic (palpably enlarged prostate) BPH. However, clinically significant BPH necessitating treatment will develop in only 50% of men with an enlarged prostate gland. In the United States, the estimated risk of a 50-year-old man undergoing a prostatectomy in his lifetime is approximately 25% to 40%. If left untreated, a significant number of symptomatic patients will remain stable or improve without adverse sequelae.