The relative amount of epithelium, muscle, connective tissue and lumen in prostatic hyperplasia as a function of the mass of tissue resected.

PURPOSE

The relative amounts of epithelium, connective tissue, muscle and gland lumen in benign prostatic hyperplasia have been reported but they have not been correlated with prostate size. We determine if the relative amount of prostatic tissue varies with prostate size.

MATERIALS AND METHODS

Paraffin blocks of transurethrally resected prostate tissue were randomly chosen from the archives of 58 patients with benign prostatic hyperplasia. Two new slides per patient were made and stained with prostate specific antigen or Masson trichrome, respectively. A total of 20 images from each slide were captured using a high resolution camera, digitized and analyzed with computer software for the relative percentage of the various tissue components.

RESULTS

As the amount of prostate tissue resected increased from less than 10 to greater than 70 gm. the epithelium had a 4-fold increase from 5.37 to 21.92%, the muscle component had a 42% decrease from 28.46 to 16.62%, the lumen doubled from 7.05 to 14.01% and the connective tissue remained relatively unchanged from 35.58 to 31.53%. There was a statistically significant difference in all components of prostatic tissue except for connective tissue when comparing prostates less than 30 versus greater than 30 gm., including epithelium 6.52 versus 16.10% (p <0.01), muscle 28.45 versus 20.78% (p <0.01), lumen 7.42 versus 14.58% (p <0.01) and connective tissue 35.74 versus 32.45% (p <0.06). The stroma-to-epithelium and muscle-to-epithelium ratios each had a 9-fold decline (p = 0.01).

CONCLUSIONS

As the prostate increases in size, there is statistically significant more epithelium and lumen, and less muscle tissue.