Immunocytochemical demonstration of prostatic acid phosphatase: different secretion kinetics between normal,...

The ultrastructural localization and distribution of prostatic specific acid phosphatase in normal, hyperplastic and neoplastic human prostates was studied by immunocytochemical methods. In normal or hyperplastic prostates, the localization of prostatic specific acid phosphatase was uniformly observed at the apical portion of the glandular epithelium of apical cells under the light microscope. Electron microscopy revealed prostatic specific acid phosphatase localized in the microvilli lining prostatic and vesicular bodies of apical cells. Occasionally the limiting membrane of the blebs and vesicles extruded into the glandular lumen and were stained positively. Light microscopic examination of neoplastic prostates revealed a more intense and uniform staining of tumor cells and the glandular epithelium of well differentiated adenocarcinomas, whereas less intense and more variable staining was seen in neoplastic cells of moderately or poorly differentiated adenocarcinomas. Furthermore, under electron microscopic study, prostatic specific acid phosphatase granules were uniformly and intensely condensed in intracytoplasmic vacuoles in well differentiated adenocarcinomas, whereas in moderately or poorly differentiated adenocarcinomas 2 types of staining were observed. Among neoplastic cells, positive granules with less intensity were found between collagen fibers as well as adjacent to the endothelium of the stromal capillaries in anaplastic tissue.