Primary Extra-Uterine Endometrial Stromal Sarcoma and Synchronous Breast Cancer: A Double Whammy: A Case report.

Endometrial stromal sarcoma is an uncommon gynecological tumor. Extra-uterine endometrial stromal sarcoma (EESS), the extra-uterine variant of its relatively more common counterpart, is even rarer with only few documented case reports. We report a case of a 40-year woman with bilateral adnexal tumors and synchronous invasive ductal breast carcinoma (IDC) posing a diagnostic challenge. The histopathology of specimen confirmed the diagnosis of EESS in the absence of florid endometriosis and synchronous hormone-positive infiltrating duct cancer in the breast. Patient was started on adjuvant endocrine therapy and is disease free at the end of 2 years. To the best of our knowledge, this is the first documentation of synchronous presentation of IDC and EESS, highlighting the possible role of hyper-estrogenemia as an etiological factor. © Federation of Obstetric & Gynecological Societies of India 2021.