Incidence and clinical characteristics of unexpected uterine sarcoma after hysterectomy and myomectomy for uterine fibroids: a retrospective study of 10,248 cases

BACKGROUND Uterine fibroids often require a hysterectomy or myomectomy via laparotomy or laparoscopy. Morcellation is often necessary to perform a laparoscopic surgery. The objective of this study is to determine the incidence of unexpected uterine sarcomas (UUSs) after hysterectomy and myomectomy for uterine fibroids and to reduce the occurrence and avoid the morcellation of UUSs by analyzing their characteristics. METHODS Women who had a hysterectomy or myomectomy for uterine fibroids in Shengjing Hospital of China Medical University between November 2008 and November 2014 were selected for the study, and their clinical characteristics were analyzed. RESULTS During the period, 48 UUSs were found in 10,248 cases, and the overall incidence was 0.47%. There was no statistical difference (P=0.449) regarding the incidence (0.50% vs 0.33%) between 42 UUSs in 8,456 cases undergoing laparotomy and six UUSs in 1,792 cases undergoing laparoscopy. Most of the UUSs were stage I (89.58%), which occurred more commonly (56.25%) in women aged 40-49. Abnormal uterine bleeding (39.58%) was the main clinical manifestation. Rapidly growing pelvic masses (12.5%), rich blood flow signals (18.75%), and degeneration of uterine fibroids (18.75%) prompted by ultrasonography may suggest the possibility of UUSs. The margins of most UUSs (93.75%) were regular, which may cause UUSs to be misdiagnosed as uterine fibroids. Fifteen cases underwent magnetic resonance imaging examinations. Approximately 73.33% showed heterogeneous and hypointense signal intensity on T1-weighted images, and 80% showed intermediate-to-high signal intensity on T2-weighted images, with necrosis and hemorrhage in 40% of cases. After contrast administration, 80% presented early heterogeneous enhancement. CONCLUSION The incidence of UUSs after hysterectomy and myomectomy for uterine fibroids was low, and their clinical characteristics are atypical. It is necessary and very critical to make a complete and cautious preoperative evaluation to reduce the occurrence and avoid the morcellation of UUSs.