Benign prostatic hyperplasia (
BPH), also called
benign enlargement of the prostate (
BEP or
BPE),
adenofibromyomatous hyperplasia and
benign prostatic hypertrophy (technically incorrect usage), is a benign (noncancerous) increase in size of the
prostate. BPH involves
hyperplasia of prostatic
stromal and
epithelial cells, resulting in the formation of large, fairly discrete nodules in the transition zone of the prostate. When sufficiently large, the nodules impinge on the
urethra and increase resistance to flow of urine from the bladder. This is commonly referred to as "obstruction," although the urethral
lumen is no less patent, only compressed. Resistance to urine flow requires the bladder to work harder during voiding, possibly leading to progressive
hypertrophy, instability, or weakness (atony) of the bladder muscle. BPH involves hyperplasia (an increase in the number of cells) rather than hypertrophy (a growth in the size of individual cells), but the two terms are often used interchangeably, even among
urologists. Although
prostate specific antigen levels may be elevated in these patients because of increased organ volume and
inflammation due to
urinary tract infections, BPH does not lead to cancer or increase the risk of cancer.