Introduction Uterine morcellation in minimally invasive surgery has recently come under scrutiny because of inadvertent dissemination of malignant tissue, including leiomyosarcomas commonly mistaken for fibroids. Identification of preoperative risk factors is crucial to ensure that oncologic care is delivered when suspicion for malignancy is high, while offering minimally invasive hysterectomies to the remaining patients.

Objectives The aim of this study was to characterize risk factors for uterine leiomyosarcomas by reviewing preoperative, intraoperative, and postoperative data with an emphasis on the presence of concurrent fibroids.

Methods A retrospective case-control study of women undergoing hysterectomy with pathologic diagnosis of uterine leiomyosarcoma at a tertiary care center between January 2005 and April 2014.

Results Thirty-one women were identified with leiomyosarcoma and matched to 124 controls. Cases with leiomyosarcoma were more likely to have undergone menopause and to present with larger uteri (19- vs 9-week sized), with the most common presenting complaint being a pelvic mass (35.5% vs 8.9%). Controls were ten times more likely to have undergone a tubal ligation (30.6% vs 3.2%). Endometrial sampling detected malignancy preoperatively in only 50% of cases. Leiomyosarcomas were more commonly present when pelvic masses were identified in addition to fibroids on preoperative imaging. Most leiomyosarcoma cases (77.4%) were performed by oncologists via an abdominal approach (83.9%), with only 2 of 31 leiomyosarcomas being morcellated. Comparative analysis of preoperative imaging and postoperative pathology showed that in patients with leiomyosarcoma, fibroids were misdiagnosed 58.1% of the time, and leiomyosarcomas arose directly from fibroids in only 6.5% of cases.

Conclusions Leiomyosarcoma risk factors include older age/postmenopausal status, enlarged uteri of greater than 10 weeks, and lack of previous tubal ligation. Preoperative testing failed to definitively identify leiomyosarcomas, although the presence of synchronous pelvic masses in fibroid uteri should raise clinical suspicion. Given the difficulty of preoperative identification, future efforts should focus on the development of safer minimally invasive techniques for uterine morcellation.