Prostatism: Pathology
Prostatism is the clinical syndrome consisting of the symptoms associated with outlet obstruction at the bladder neck. By far the commonest cause of this syndrome is benign prostatic hypertrophy, but other entities such as bladder neck stenosis and urethral strictures can produce these symptoms as well.
Prostatic hypertrophy is in fact a hyperplasia of epithelial and fibromuscular elements arranged in multicentric nodules and originating in the periurethral part of the gland. As the hyperplastic process continues, the nodules coalesce into lobes which compress the outer prostate into a false or ‘surgical’ capsule. The surgery for benign prostatic disease (open or transurethral) involves removal of these lobes down to the level of this capsule, but does leave the outer prostate behind and therefore does not prevent subsequent development of carcinoma.
Although eight anatomic types of prostatic obstruction have been described, for practical purposes most obstruction consists of lateral lobe hypertrophy plus or minus median lobe involvement. Cystoscopically, this is visualized as two large lobes coming in from both sides laterally and as the instrument goes beyond, it may or may not have to go up over a prominent median lobe before entering the bladder. This anatomical information is of some significance when trying to catheterize a patient with prostatic obstruction.
The prostate can be palpated rectally. It is normally rubbery, firm and because of the usual lateral lobe involvement, the median sulcus is normally preserved. The apex (distal portion) is usually narrower than the base (bladder neck area) and normally the benign gland is relatively symmetrical — but asymmetry does not necessarily mean malignancy. Normal adult prostate size would be roughly two centimeters in diameter. Most urologists, however, describe prostatic size as a measure of volume by weight. This may seem a little strange, but relates to the pathologist’s initial description of the surgically removed gland in grams; thus a normal adult size prostate would be 10-20 grams in size. Commonly, benign prostatic hypertrophy involves a gland of approximately 30 to 40 grams in size, but certainly adenomas removed at open prostatectomies have been weighed at over 200 grams.