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.