Immunohistochemical detection of estrogen and progesterone receptors in the normal urinary bladder and in pseudomembranous trigonitis.

According to recent studies showing the presence of estrogens receptors (ERs) in the human female lower urinary tract, we performed ER and progesterone receptor (PR) assays in fresh frozen and paraffin embedded biopsies taken from the urinary bladder. Fourteen females undergoing endoscopy during staging for gynecological cancer (endometrium, cervix, ovary) and 15 women complaining of recurrent abacterial cystitis (pseudomembranous trigonitis) were enrolled in the study as Group 1 and Group 2, respectively. After informed consent, they were submitted to cystoscopy, during which two biopsies were taken: one on the trigonum and the other on the bladder lateral wall. ERs were identified in both groups only in the trigonum (7/14 patients in Group 1 and 8/15 in Group 2), whereas the bladder lateral wall always stained negative. PRs were found at both sites in both groups (11/14 cases on the trigonum and 7/14 on the bladder lateral wall in Group 1; 11/15 and 2/15 respectively in Group 2). Morphological localization of PRs showed intense omogeneous staining in the nuclei of the stromal fibroblasts too. A clear correspondence between the presence of steroid receptors at the squamous metaplasia of the trigonum was observed. These data are discussed speculating about a possible endocrine pathogenesis of pseudomembranous trigonitis.