BPH is characterized by an increase in epithelial and stromal cell numbers (hyperplasia) in the peri-urethral area of the prostate. New epithelial gland formation is normally only seen during foetal development.

The development of new glands in the adult prostate has given rise to the concept of ‘reawakening’ of the inductive effect of the prostatic stroma on the prostatic epithelium.

The increase in prostate cell number could reflect proliferation of epithelial and stromal cells, impairment of programmed cell death, or a combination of both. During the early phases of development of BPH, cell proliferation occurs rapidly.

In established BPH, cell proliferation slows down and there is impairment of programmed cell death (androgens and oestrogens actively inhibit cell death).