Primary low-grade extrauterine endometrial stromal sarcoma: analysis of 10 cases with a review of the literature

BACKGROUND: This study aimed to analyze the clinical and pathological features of extrauterine endometrial stromal sarcoma (EESS) and explore an effective therapeutic regimen to reduce the recurrence rate in low-grade EESS patients. METHODS: Ten LG-EESS patients who were treated at the Chinese Academy of Medical Sciences Cancer Institute and Hospital from June 1999 to June 2019 were collected and analyzed. RESULTS: (1) Patient demographics are summarized in manuscript. Preoperative CA125 examination showed that 8 patients had a median level of 49.5 U/L (15.4–168.0 U/L). (2) All ten patients underwent tumor cytoreductive surgery. Five patients underwent optimal tumor resection and achieved an R0 resection. After the initial surgery, 7 patients who had multiple metastasis were treated with adjuvant chemotherapy, 2 patients with vaginal ESS were treated with chemotherapy and radiation therapy, and 6 patients with ER/PR positive received hormone therapy with or without chemotherapy. (2) Most EESS patients had multiple tumors. The omentum was the most commonly affected site, followed by the ovaries. (3) The median follow-up was 94 (range: 27–228) months, and recurrence was observed in 3 patients (n = 10, 30%) who underwent non-optimal surgery and no hormone therapy. The 5-year and 10-year DFS rates were both 70%, as shown in Fig. 2. OS was both 100% at 5 and 10 years. CONCLUSION: As a conclusion, EESS is a rare disease and LG-EESS has a good prognosis. Surgery remains the available treatment for patients. LG-EESS has a risk of late recurrence which requires a long-term follow-up. With a limited sample size, our study shows optimal tumor reductive surgery and adjuvant hormone therapy may significantly reduce the risk of recurrence.