(I) Definition Benign prostatic hyperplasia is one of the most common benign diseases causing urinary disturbances in middle-aged and elderly men. It is mainly characterized by histological hyperplasia of the interstitial and glandular components of the prostate, anatomical enlargement of the prostate, clinical symptoms dominated by lower urinary tract symptoms, and urodynamic obstruction of the bladder outlet. (ii) Epidemiology The incidence of histologic BPH increases with age, usually occurring initially after age 40, to >50% by age 60, and up to 83% by age 80. Similar to the histologic presentation, symptoms such as dyspareunia increase with age. Approximately 50% of men with a histologic diagnosis of BPH have moderate to severe lower urinary tract symptoms. Some studies have shown that it appears that Asians are more prone to moderate-to-severe BPH-related symptoms than Americans. (iii) Etiology Two important conditions must be present for the development of BPH: aging and a functioning testis. Domestic scholars investigated 26 elderly eunuchs of the Qing Dynasty and found that the prostate gland had become completely inaccessible or significantly atrophied in 21 of them. However, the specific mechanism by which BPH occurs is unclear and may be caused by a balanced disruption of epithelial and mesenchymal cell proliferation and apoptosis. The associated factors are: androgens and their interaction with estrogens, interaction of prostatic mesenchymal a glandular epithelial cells, growth factors, inflammatory cells, neurotransmitters and genetic factors. (iv) Pathology McNeal divided the prostate into peripheral zone, central zone, migratory zone and periurethral glandular area. All BPH nodules occur in the migratory zone and periurethral glandular region. Early nodules in the periurethral glandular region are entirely mesenchymal in composition; whereas early nodules in the migratory zone show mainly hyperplasia of glandular tissue with a relative decrease in the amount of mesenchyme. The smooth muscle in the interstitial tissue is also an important component of the prostate. These smooth muscles and the periurethral tissue of the prostate are innervated by adrenergic nerves, cholinergic nerves, or other enzymatic transmitters, with the adrenergic nerves playing a major role. There are abundant G receptors in the prostate and bladder neck, especially αl receptors, and activation of this adrenergic receptor can significantly increase prostatic urethral resistance. The anatomical envelope of the prostate and lower urinary tract symptoms are closely related. Due to the presence of this envelope, the hyperplastic gland is compressed and bulges out into the urethra and bladder, thereby increasing urinary tract obstruction. After prostate enlargement, the enlarged nodules compress the rest of the gland to form a “surgical envelope” with a clear demarcation between the two. After surgical removal of the hyperplastic part, the compressed gland remains, so that the prostate gland can still be detected by postoperative rectal examinations and imaging. (E) Pathophysiological changes Prostatic hyperplasia leads to prolongation of the posterior urethra, deformation and narrowing of the urethra under pressure and increased urethral resistance, causing bladder hypertension and symptoms associated with the voiding phase. With the increase of bladder pressure, compensatory hypertrophy of the bladder forcing muscle occurs, and the forcing muscle becomes unstable and causes symptoms related to the urinary storage phase. If the obstruction is not relieved for a long time, the forceps muscle loses its compensatory capacity. The main causes of upper urinary tract changes secondary to BPH, such as hydronephrosis and impaired renal function, are urinary retention due to bladder hypertension and ureteral reflux. (VI) Clinical manifestations, diagnosis and treatment The main clinical manifestations of BPH include bladder irritation, obstructive symptoms and related comorbidities. Various symptoms may appear sequentially or develop progressively throughout the course of the disease. The diagnosis is based on symptoms, physical examination, especially rectal examination, imaging, urodynamic examination and endoscopy, etc. The treatment of BPH mainly includes observation and waiting, drug treatment, minimally invasive treatment and surgical treatment. The aim of treatment is to improve the quality of life of patients while protecting renal function. The choice of specific treatment methods should be based on the severity of the patient’s symptoms, combined with various auxiliary examinations, local medical conditions and patient compliance.