The Preliminary Study On BPH In Prostatic Outer Gland By Transrectal Ultrasound And Pathologic Examination

Objective: To study the possibility of benign prostatic hyperplasia(BPH) in prostatic outer gland by transrectal ultrasound (TRUS) andpathologic examination.Material and methods:1. Sixty-nine patients who underwent TRUS-guided biopsies of the prostate gland were the subjects of this study. According to whether there is a hypoechoic nodule in prostatic outer gland on sonogram, patients were divided into non-nodular group (n=27) and nodular group (n=42). Of the non-nodular group, 20 patients underwent biopsies of the outer glands on both sides. The remainders were biospied on a single side. A total of 47 sites were biopsied, each site was biopsied in sagittal and longitudinal plane respectively, 2 biopsies per site (n=94). Of the nodular group, each nodule was biopsied twice (n=84).2. Whole prostate specimens obtained at autopsy from 16 men who died from non- prostate related causes were studied. Sonogram of the specimens was investigated by putting them in water, then thespecimens were sliced down perpendicular to the urethra, histologically processed and stained by HE methods.3. Pathologists in double blind diagnosed the 85 specimens from the prostatic outer glands obtained through biopsy or autopsy independently.4. In the nodular group, pathological diagnosis of BPH was confirmed in 22 nodules. A combination of HE staining, immunohistochemisty staining and computer assisted quantitative image analyses were adopted to determine the mean percent area densities of stroma, epithelium, glandular lumen and smooth muscle component. Results:1. Biopsy:(1) Non-nodular group: Symmetric enlargement of the inner glands was observed in 20 patients, 9 outer glands became thin because of the compression, 18 outer glands showed no obvious sign of compression. BPH was established in all the 47 outer gland sites.(2) Nodular group: BPH was established in 22 patients (52.4%).2. Autopsy:The specimens obtained at autopsy were examined by nude-eye. Aclear-cut interface between inner gland and outer gland and multiple cysts was observed. Six cases had well-marginated round nodules within the outer gland. Four of them had a single nodule and 2 had multiple nodules. The outer glands in other ten cases without nodular changes became slightly thin due to compression. Sonogram findings were consistent with that of nude-eye observation. A hypoechoic nodule measuring 0.5x0.6cm beneath the membrane on sonogram corresponded well with the nodule seen on autopsy. Pathological diagnosis of BPH of the outer glands were made in all HE-stained autopsy specimens with varying degrees of hyperplasia of the glands, small muscle and stroma. Hyperplastic nodules were found in twelve cases.3. Of the nodular group, 22 nodules within the outer glands were established to be BPH nodules. The area density of stroma, epithelium and glandular lumen was 75.52 ±13.14%, 20.57±9.01% and 6.85±4.51% respectively. The area percentage of smooth muscle component in stroma was 24.14±6.31%.Conclusion:1. Just like the inner gland, hyperplasia of the prostatic outer glandcould occur because it is also a glandular tissue.2. It is possible that a hypoechoic nodule in outer gland on sonogram may be benign hyperplasia nodule, besides PCa, PIN and so on..3. Our study suggests that the proportion of elements may be different between inner gland and the hypoechoic hyperplasia nodule in the outer gland.