Primary extrauterine endometrial stromal sarcoma with multiple organ invasion: A case report

Abstract Background: Primary extrauterine endometrioid stromal sarcoma (EESS) are rarer tumors that occur outside the uterus and do not involve the uterus. Case presentation: We report a case of low-grade extrauterine endometrial stromal sarcoma of the pelvic and colorectum. A 46-year-old woman, who complained of diarrhea with yellow mucus-like or elongated stools for more than 2 months, came to our hospital with colonoscopy and CT results that raised suspicion of colorectal cancer but also pathological examination results indicative of endometriosis. As the intraoperative pathology of the omentum and ovary revealed endometrial stromal sarcoma, and part of the sigmoid and rectum were obviously thickened and stiff, we performed cytoreductive surgery including removal of the uterus, bilateral fallopian tubes, bilateral ovaries, part of the colorectum, omentum majus, and metastatic lesions. Postoperative pathology revealed that the pelvic mass and segments from the colorectum were consistent with low-grade endometrial stromal sarcoma. Long-term oral administration of Letrozole, 2.5mg/day and Farlutal, 500mg/day was prescribed. During follow-up of the patient, the pelvic peritoneal examination results were negative, and has remained disease-free at 48-months post-surgery. Conclusion: We report a rare case of simultaneous endometrial stromal sarcoma of the pelvic and colorectum.