Unexpected uterine sarcomas after hysterectomy and myomectomy for presumed leiomyoma: a retrospective study of 26,643 patients.

Objectives: We conducted this study to explore the clinical characteristics, prognosis, and prevalence of unexpected uterine sarcoma (UUS) after hysterectomy and myomectomy for presumed leiomyoma. Study design: The records of women who underwent hysterectomy or myomectomy through laparoscopy or laparotomy for preoperatively presumed uterine leiomyomas from January 2009 to December 2016 were reviewed and data were retrospectively analyzed. Results: Eleven patients had morcellation of uterine sarcoma. Eighty-eight patients were diagnosed with uterine sarcomas (total prevalence: 0.33%) including 29 leiomyosarcomas (LMS), 48 endometrial stromal sarcomas (ESS), and 11 adenosarcomas. ESS patients with advanced stage were significantly associated with worse overall survival (p<0.01). Conclusion: Only 0.33% of patients who underwent surgery for presumed leiomyoma experienced UUS, and advanced stage seemed to be the single prognostic factor for sarcoma. However, the time interval between initial treatment and secondary definitive surgery was not shown to impact prognosis. In addition, the small number of UUS patients having morcellation (4 LMS and 7 ESS) may be underpowered to detect differences in survival.