Aim. To examine the structure of the prostate tissue in patients with III B chronic prostatitis (CP) and chronic pelvic pain syndrome (CPPS).
Materials and methods. The study analyzed transrectal fine-needle biopsy specimens of 10 patients with the verified diagnosis of chronic pelvic pain syndrome/category III B chronic prostatitis (CPPS/IIIB CP) according to the National Institutes of Health classification. Tissues were examined using light and electron microscopy, and immunohistochemical study of the expression of CD31, CD34, NSE and S-100 markers.
Results. All biopsy specimens of all patients showed fibroplastic changes of the prostate tissue most markedly pronounced in the stroma and muscle fibers in the form of total fibrosis, myofibril atrophy, and extracellular lipofuscin deposition. The examination revealed a significant reduction in the density of microcirculatory bed vessels and arteriolar luminal stenosis, a reduction in the number of nerve fibers, and compression of their fibrous tissue. No inflammatory changes were found in the prostate.
Discussion. In patients with CPPS/IIIB CP, the changes in the prostate at the microscopic and ultrastructural levels are characteristic of severe chronic tissue hypoxia, which leads to the development of fibrosis resulting in stenosis of microcirculatory bed vessels and degenerative changes in nerve fibers and cells. No signs of an inflammatory reaction in the examined tissue were established.
Conclusion Changes in the prostate tissue in CPPS/IIIB CP suggest the presence of chronic pelvic ischemia and exclude its association with inflammation as the main pathological process.

Keywords: transrectal biopsy, morphological evaluation, prostate gland, chronic pelvic pain syndrome, ischemia