Three-Dimensional Arrangement of Muscle Fibers, Collagen and Elastin Fibers of the Proximal Prostatic Urethra in Benign Prostatic Hyperplasia / 대한비뇨기과학회지

ABSTRACT

PURPOSE: Anatomical change of the prostatic stroma, that is benign prostatic hyperplasia, results in a functional change which manifests as lower urinary tract symptoms (LUTS). We observed/investigated whether there are structural changes in the three-dimensional arrangement of muscle, collagen and elastin fibers of the prostatic urethra which can be another possible mechanism of LUTS. MATERIALS AND METHODS: Hyperplastic nodules, which were surgically en bloc resected, and normal prostate from radical cystectomy specimens were examined. Surgical specimens were fixed in formalin and sectioned serially in a transverse plane along the lumen of the upper segment of the prostatic urethra. Additional sagittal sections were also made serially. All tissue blocks were 2mm thick. All slides were prepared with hematoxylin-eosin, Masson-trichrome and Verhoeff's elastin stain. RESULTS: Muscle and collagen fibers surrounding prostatic acini seemed poorly oriented and blended with the outermost fibers of the urethra. Muscle and stromal fibers surrounding the prostatic urethra seemed to be stretched and oriented mainly in the longitudinal direction with small fibroblastic nodules in the periurethral stroma. A periurethral gland structure was observed between the urethral wall in which the fiber was arranged longitudinally. Circular muscle fibers were not observed in the periurethral area, indicating that the surgical capsule resulted from urethral muscle fibers. CONCLUSIONS: Apparent changes to the 3-dimensional arrangement of collagen, elastin and muscle fibers surrounding the acini and prostatic urethra were not observed in the proximal prostatic urethra or the bladder neck, except that the fibers surrounding the urethra were stretched.