Benign prostatic hyperplasia (BPH) refers to the nonmalignant growth of the prostate gland, and is histologically defined as hyperplasia of the prostate gland. BPH is an age-related phenomenon in men beginning at about age 40 years. BPH may ... Benign prostatic hyperplasia (BPH) refers to the nonmalignant growth of the prostate gland, and is histologically defined as hyperplasia of the prostate gland. BPH is an age-related phenomenon in men beginning at about age 40 years. BPH may result in prostatic enlargement and clinical symptoms most commonly affecting the lower urinary tract. These symptoms may be obstructive, including hesitancy, weak flow, and urinary retention, or irritative, including increased frequency and urgency. However, not all men with histologic BPH will develop prostatic enlargement or urinary symptoms (review by Roehrborn, 2005).