Benign prostatic hypertrophy (BPH) is extremely common 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.
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
An enlarged prostate may also be incidentally found on imaging of the pelvis or on rectal exam.
Bening 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).
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 30cc ( (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 lifiting medially (J-shaped ureters or Fishhook ureters). Chronic bladder outlet obstruction can lead to detrusor hypertrophy , trabecullation and formation of bladder diverticula.
Not typically used to asses the prostate, BPH is more frequently an incidental finding. Extension above the symphasis 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 around its periphery.
Treatment and prognosis
Treatment 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.
Complications of untreated benign prostatic hypertrophy include 4:
- 1. Weissleder R, Wittenberg J, Harisinghani MG. Primer of diagnostic imaging. Mosby Inc. (2007) ISBN:0323040683. Read it at Google Books - Find it at Amazon
- 2. Ishida J, Sugimura K, Okizuka H et-al. Benign prostatic hyperplasia: value of MR imaging for determining histologic type. Radiology. 1994;190 (2): 329-31. Radiology (abstract) - Pubmed citation
- 3. Prostate Hyperplasia, Benign by Raymond J Leveillee from emedicine.com. Prostate Hyperplasia, Benign
- 4. Grossfeld GD, Coakley FV. Benign prostatic hyperplasia: clinical overview and value of diagnostic imaging. Radiol. Clin. North Am. 2000;38 (1): 31-47. - Pubmed citation
Synonyms & Alternative Spellings
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