Abstract
Extrauterine endometrial stromal sarcomas (EUESSs) are rare tumours occurring without primary uterine involvement. They are classified as primary or secondary, depending on uterine involvement by stromal sarcomas. A 56-year-old woman who earlier underwent bilateral modified radical mastectomy for adenocarcinoma and total abdominal hysterectomy for endometrial stromal sarcoma, followed by tamoxifen therapy, presented with left loin pain. On evaluation, she had a left renal calculus with hydroureteronephrosis. Before percutaneous nephrolithotripsy, ureteroscopy revealed a polypoidal mass that was diagnosed as EUESS. The mass arose primarily within the ureteral lumen, with periureteric tissue uninvolved. She underwent left radical nephroureterectomy with adjuvant hormonal treatment. This is probably the first case of EUESS arising de novo from within the ureteral lumen without endometriosis, to be reported in medical literature. Immunohistochemistry facilitates earlier diagnosis. Cytoreductive surgery is the definitive treatment and multidisciplinary approach helps in overall survival of the patient.