Persistently elevated estradiol after bilateral salpingo-oophorectomy in recurrent low-grade endometrial stromal sarcoma: a case report.

Background: Low-grade endometrial stromal sarcoma (LGESS) is a rare uterine mesenchymal neoplasm that frequently expresses estrogen and progesterone receptors. Endocrine therapy is a cornerstone of treatment for recurrent or metastatic LGESS. In premenopausal patients, bilateral salpingo-oophorectomy (BSO) is commonly performed to reduce endogenous estrogen production and would be expected to result in a postmenopausal hormonal profile. Case: We report the case of a patient with recurrent, metastatic estrogen receptor (ER)/progesterone receptor (PR)-positive LGESS who had previously undergone BSO. Her disease initially responded to aromatase inhibitor therapy; however, she subsequently experienced pulmonary progression, including a large endobronchial metastasis requiring bronchoscopic cytoreduction. Despite pathologically confirmed BSO, further evaluation revealed a hormone profile more consistent with persistent premenopausal estrogen exposure. Given concern that ongoing estrogen exposure may have been contributing to progression of this hormone-sensitive malignancy, treatment was changed to combined leuprolide and letrozole. Three months after initiation of combined endocrine therapy, imaging demonstrated a partial response, which was confirmed at 6 months, accompanied by estradiol levels in the postmenopausal range. Conclusion: This case raises the possibility that surgical menopause may not always result in complete estrogen deprivation in LGESS. Potential explanations include assay limitations, undetectable residual gonadotropin-responsive steroidogenic tissue, peripheral aromatization, and tumor-associated estrogenic activity. Biochemical evaluation of estrogen status may be informative in select patients whose disease behavior appears discordant with presumed post-oophorectomy menopausal status.