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Benign prostatic hypertrophy

Benign prostatic hypertrophy (BPH) is an extremely common condition in elderly men and is a major cause of outflow obstruction. Although the term prostatomegaly is often used interchangeably, strictly speaking prostatomegaly may refer to any cause of prostatic enlargement. 


By the age of 60, 50% of men have BPH, and by 90 years of age the prevalence has increased to 90%. As such it is often thought of essentially as a 'normal' part of ageing 1.

Clinical presentation

Although a degree of prostatomegaly may be completely asymptomatic, the most common presentation is with lower urinary tract symptoms (LUTS) including 1-4

  • poor stream despite straining
  • hesitancy, frequency and incomplete emptying of the bladder
  • nocturia

An enlarged prostate may also be incidentally found on imaging of the pelvis or on rectal exam. 


Benign prostatic hypertrophy is due to a combination of stromal hypertrophy and glandular hyperplasia, predominantly of the central zone (as opposed to prostate cancer which typically originates in the peripheral zone).

Complications of untreated benign prostatic hypertrophy include 4:

Radiographic features


Ultrasound has become the standard first line investigation after the urologist's finger. Typically there is an increase in volume of the prostate with a calculated volume exceeding 30 cc ((A x B x C)/2). The central gland is enlarged, and is hypoechoic or of mixed echogenicity. Calcification can be seen both within the hypertrophied gland as well as in the pseudocapsule (representing compressed peripheral zone).

Post-micturition residual volume is typically elevated.

Fluoroscopy: IVP

The bladder floor can be elevated and the distal ureters lifted medially (J-shaped ureters or Fishhook ureters). Chronic bladder outlet obstruction can lead to detrusor hypertrophy, trabeculation and formation of bladder diverticula.


Not typically used to assess the prostate, BPH is more frequently an incidental finding. Extension above the symphysis pubis was used as a marker on axial imaging, however now that volume acquisition and coronal reformats are standard, the same criteria as on US can be used (>30 cc)


Typically demonstrates the enlarged central zone to be heterogenous in signal with an intact low signal pseudocapsule in its periphery.

Treatment and prognosis

Medical management for early disease typically commences with finasteride (a 5-alpha-reductase inhibitor).

Surgical management for symptomatic patients is typically with a transurethral resection of the prostate (TURP), and careful patient selection is important given the high prevalence of both BPH and lower urinary symptoms (LUTS) in this population.

Urodynamic studies and prostate size estimation are often used to guide therapy, although prostate size in isolation is a poor predictor of symptom severity 4

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