Morphometry of the prostate: I. Distribution of tissue components in hyperplastic glands

Morphometry, or quantitative image analysis, offers great promise in characterizing the various histologic types of benign prostatic hyperplasia (BPH), but to date, a systematic study of the tissue components is lacking. Thus we employed morphometry to examine the distribution of primary BPH tissues throughout whole human prostates.

The prostate glands of 20 men with BPH were removed for low-volume carcinoma and subjected to a uniform, comprehensive, systematic quantification of the primary BPH tissue components using the technique of digitization and point-count morphometry.

We found the following average volumes among the 20 glands: epithelium, 19.9% (S.D. 5.1%, range 11.7% to 30.8%); fibromuscular stroma, 50.4% (S.D. 9.4%, range 32.2% to 74.4%); glandular lumina, 29.7% (S.D. 8.9%, range 11.9% to 47.5%). Within the individual prostates, we found symmetry in primary BPH tissue distribution, except that the outer prostate was on average 25% richer in epithelium than the inner prostate (p < 0.05). When tissue composition was determined in simulated biopsy specimens, corrected for radial (ie, inner vs outer gland) orientation, the correlation with whole-organ composition was statistically significant for "percentage epithelium" (r = 0.72, p < 0.01) and for "stromal/epithelial ratio" (r = 0.63, p < 0.01).

Major differences in primary tissue composition may separate different hyperplastic prostates. Primary BPH tissues are rather symmetrically distributed within individual prostates. Quantitative histologic differences between prostates, potentially important in clinical decision-making may be accurately diagnosed by morphometry of radially oriented biopsy specimens.