Estrogen synthesis by Brenner tumors

Conversion of circulating estrone sulfate to 17beta-estradiol by ovarian tumor tissue: a possible mechanism behind elevated circulating concentrations of 17beta-estradiol in postmenopausal women with ovarian tumors

AIM

Elevated serum levels of 17beta-estradiol (E2) are frequently found in postmenopausal women with ovarian tumors not classified as estrogen-producing. Conversion of circulating estrone sulfate (E1S) to E2 is one alternative way of E2 formation in target tissues in postmenopausal women. Our aim was to find out if conversion of circulating E1S to E2 by the tumor tissue could be a reason for elevated serum E2 levels in postmenopausal women with 'non-estrogen-producing' ovarian tumors.

METHOD

Serum E2 was measured in 12 postmenopausal women with 'non-estrogen-producing' ovarian tumors (nine benign, three malignant). Total hydrolysis of and [3H]E2 formation from [3H]E1S by the tumor tissue homogenates was studied in vitro.

RESULTS

Serum E2 showed significant positive correlations with total hydrolysis of and [3H]E2 formation from [3H]E1S in the total material as well as in the benign tumor subgroup. [3H]E2 formation was the most important independent variable.

CONCLUSION

Conversion of circulating E1S to E2 by the tumor tissue could be one important reason for elevated S-E2 levels in postmenopausal women with 'non-estrogen-producing' ovarian tumors.

Brenner tumor of the ovary with extensive stromal luteinization presenting in pregnancy: report of a case and review of the literature

Brenner tumor in pregnancy is rare, with only two reported cases in association with intrauterine pregnancy. A 30-year-old woman, G1P0, was found to have an adnexal mass at 15 weeks of gestation. The mass was resected at Cesarean section and found to be a Brenner tumor with areas of stromal luteinization. Brenner tumor should be considered in the differential diagnosis of adnexal masses presenting during pregnancy. The stromal luteinization was probably related to the hormonal environment of the pregnancy.

Case report of a malignant Brenner tumor with hyperestrogenism

A rare malignant Brenner tumor of the ovary presenting with hyperestrogenism in a 79 year old woman was examined immunohistochemically and by light and electron microscopy. High pre-operative serum and urinary estrogen concentrations, low serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels, and histologically confirmed atypical endometrial hyperplasia suggested the presence of hyperestrogenism. The reduction in serum and urinary estrogen and the increase in serum LH and FSH concentrations after tumor removal confirmed that the tumor was synthesizing estrogen. Histologically, the malignant element was predominantly a squamous cell carcinoma. Transitional cell carcinoma was partially found on the cyst wall. There was a spectrum of morphologic changes between benign and malignant elements with an intermediate area with a proliferating Brenner tumor. Immunohistochemically, only the carcinoembryonic antigen was positive exclusively on the malignant element as well as in the microcyst in the benign epithelial cord, whereas all of the markers for germ cell tumors were negative. The ultrastructural features of the stromal cells were of two types: fibroblasts and steroid-producing cells. The latter type of cells might correspond morphologically to estrogen-producing cells. The present case is the fourth report showing a malignant Brenner tumor combined with apparent hyperestrogenism.

Ovarian tumors with functioning manifestations

Various categories of ovarian tumors, particularly those of gonadal stromal origin, are capable of producing a variety of hormones that occasionally induce interesting clinical manifestations. The endocrine manifestations associated with gonadal stromal tumors are often due to hormone production by the tumor cells. Sometimes the tumor cells produce only one hormone, while more frequently the hormonal manifestations result from a summation of various hormones including transformation of a variety of prehormones produced by different components of the tumor including its supportive or reactive stroma. The mechanisms involved in the production and transformation of various hormones and prehormones are complex and not thoroughly established at this time. This review will focus on gonadal stromal tumors and discuss evidence available for linkage of the clinical manifestations to hormones produced by the various neoplasms.

A case of ovarian Brenner tumor with stromal estrogenic activity

An 88-year-old menopausal Japanese female suffering from atypical genital bleeding received a left oophorectomy for a tumor of the left ovary. A vaginal smear before removal of the tumor revealed high estrogenic activity. The patient's ovarian tumor was a benign Brenner tumor and contained theca-like cells in its stroma. The pathological findings relating to these theca-like cells suggested their estrogenic activity, and a vaginal smear after removal of the tumor revealed that estrogenic activity had disappeared.

Estrogen producing activity in epithelial ovarian tumors and dermoid cysts

In 28 cases of postmenopausal women with non-functioning ovarian tumors, the estradiol (E2) level was assayed in peripheral plasma and tumor tissue extract. E2 precursors were also assayed in the tissue extract, and localization of 3beta-hydroxysteroid dehydrogenase (3beta-HSD) in the tissue was investigated. The plasma E2 levels were 153.8 +/- 205.9 pg/ml in 15 benign tumor cases, 244.3 +/- 336.5 pg/ml in 13 malignant tumor cases, and both of which were significantly higher than 12.3 +/- 3.6 pg/ml in normal postmenopausal women (p less than 0.01). The postoperative plasma E2 level (33.3 +/- 32.7 pg/ml) was significantly lower than the preoperative one (228.3 +/- 319.0 pg/ml). Twelve of 19 cases (68.2%) showed a postoperative decline in the E2 level to less than a half of the preoperative level. E2 and its precursors were found in tumor tissue. These findings demonstrate that E2 is produced by the tumor tissue itself. In addition, 3beta-HSD activity was localized in the stroma of ovarian tumors, indicating that E2 synthesis is mainly carried out in stromal cells rather than in epithelial cells.

What's new in the localization of sex steroids in the human ovary and its tumors?

It is important to understand the distribution of steroidogenesis in steroid producing tissues in order to obtain a better understanding of steroid metabolism. Recent advances in purification and subsequent generation of antibodies against cytochromes P-450 specific for steroid hormone biosynthesis have made it possible to localize the sites of steroidogenesis immunohistochemically. This review provides the localization of sex-steroid hormone biosynthesis in normal and pathological human ovaries including sex-cord stromal tumors, hyperthecosis and Brenner tumor, as determined by the tissue distribution of immunoreactivity of individual enzymes specific for different stages of the biosynthetic process.

Brenner tumor of the ovary: immunoanalysis of steroidogenic enzymes in 23 cases

Immunohistochemical analysis of cytochromes P-450 aromatase and P-450 17 alpha-hydroxylase, which catalyze the production of estrogens and androgens, respectively, was performed for 23 cases of ovarian Brenner tumor. Immunoreactivity for P-450 aromatase was observed in the epithelial cells of the tumor distinctly in two cases and faintly in four cases, while immunoreactivity for P-450 17 alpha-hydroxylase was seen in two cases. No immunoreactivity was observed in the stromal cells of the tumors, nor were luteinized cells observed in the cases examined. No correlation was observed between the immunoreactivity of cytochromes P-450 in the epithelial cells of the tumor and endometrial abnormalities. These findings, together with a review of the literature, suggest that the usual Brenner tumor is not associated with specific steroidogenesis. Rare massive Brenner tumors may, however, be capable of androgenic or estrogenic activity.

Proliferative Brenner tumor or ovarian metastases? A case report

A case of low-grade superficial transitional papillomas of the urinary bladder and concomitant bilateral ovarian tumors with close similarities to the rare proliferative Brenner tumor is reported. Due to lack of benign Brenner elements, metastases from the bladder tumors were suggested. Death was apparently related to the effect of chemotherapy, and metastases were never confirmed. In review of the case, the authors found that the morphologic appearances and biological behavior of the ovarian tumors were more consistent with a proliferative Brenner tumor than with metastases. It is pointed out that a proliferative Brenner tumor should not be excluded in the absence of benign Brenner elements when other features are characteristic. Bilateral proliferating Brenner tumors are probably not reported previously. Histogenetic implications of a combined proliferative complex of bladder papillomas and Brenner tumor are briefly discussed.