Zonal Anatomy of Prostate

Abstract

Objectives: To analyze qualitatively and quantitatively histological features (histomorphological features) of different zones of normal human prostate and its significance in histopathological diagnosis.
Material and Methods: Thirty normal prostates from men age less than 40 years, who died in traffic accidents, were inclu-ded in the study. The normal prostatic tissue consisted of four zones i.e. peripheral zone (PZ), central zone (CZ), transitional zone (TZ) and periurethral zone (PUZ). The specimens obtained were examined for qualitative and quantitative analysis of parenchyma (luminal longitudinal dimension, luminal transverse dimensions, acini and epithelial height) and stroma (smooth muscles and collagen fibers). Three random observations were made per slide and mean calculated.
Results: In all zones of the prostate the acini were distributed uniformly with columnar secretory cell lining the acini. Basal cells are found in between secretory cells and the basement membrane. In CZ, the acini were larger and polygonal than in PZ and TZ where acini were comparable and more or less rounded while in PUZ the acini are not developed. The number of acini is down regulated in PZ, CZ and TZ. Height of epithelial cells is more in CZ than in PZ and TZ. Fibromuscular stroma is compact in CZ and TZ and PUZ but loosely woven in PZ.
Conclusions: The variations in size, shape and number of acini in parenchyma and compactness or looseness of stroma were the key features for identification of different zones of prostate. As number of acini was greater in PZ, the higher incidence of adenocarcinoma in this zone was explained. Loosely woven stroma in PZ and compact stroma in TZ also explained the occurrence of adenocarcinoma from the acini of PZ and the benign prostatic hypertrophy in TZ.
Key words: Acini (Aci), Collagen Fibers (CF), Central Zone (CZ), Epithelial Height (EH), Luminal Longitudinal Dimen-sion (LLD), Luminal Transverse Dimension (LTD), Periurethral Zone (PUZ), Peripheral Zone (PZ), Smooth Muscles (SM), Transitional Zone (TZ).