Morphometric analysis of symptomatic benign prostatic hyperplasia with and without bladder outlet obstruction.

To investigate the histological features of benign prostatic hyperplasia (BPH) with and without bladder outlet obstruction (BOO), 32 patients with symptomatic BPH, 22 with BOO and ten without BOO, were studied. The area density of smooth muscle, fibrous tissue, glandular epithelium, and glandular lumen in BPH adenoma resected by transurethral surgery was estimated using morphometric analysis. No differences were found in the area density of stromal and glandular components between the two groups. In the glandular component, neither the epithelium nor lumen differed between the two groups. However, the area density of smooth muscle in the obstructed group showed a decrease compared to that in the unobstructed group (P < 0.01). We conclude that a decreased proportion of smooth muscle in BPH adenoma may play an important role in BOO.