Uterine leiomyomas are the most common benign uterine tumors [1]. A range of symptoms, from abnormal bleeding to pelvic pressure, are associated with uterine leiomyomas. Surgical management, either myomectomy or hysterectomy, is often required for the management of this form of disease. Surgical options depend on various factors, including age, childbearing requirements and patients’ preferences. Myomectomy is often a good surgical choice for patients of reproductive age who wish to bear children. Furthermore, approximately half of women with leiomyoma prefer uterus-preserving treatment, even after childbearing is completed [2].

Myomectomy or subtotal hysterectomy is the one of the most commonly performed gynecologic surgeries. With recent advances in minimally invasive surgery, laparoscopic myomectomies or hysterectomies have become common practices. Although a major concern with laparoscopic surgery is the removal of large myoma through small incisions, the introduction of morcellation has solved this problem. However, the US Food and Drug Administration (FDA) has issued a statement discouraging the use of power morcellation for hysterectomy and myomectomy due to the fear of potentially disseminating an occult uterine sarcoma [3].

In uterus-preserving surgery, such as myomectomy or subtotal hysterectomy, there may be concerns about tumor aggression, even when morcellation is not used. However, there is limited literature on the management of uterine sarcoma found incidentally after myomectomy or subtotal hysterectomy for presumed uterine leiomyoma [4, 5]. The aims of this study were to evaluate the outcomes of patients with uterine sarcoma found incidentally after initial uterus-preserving surgery for presumed benign disease and to investigate the role of surgical re-exploration in this disease subset.

After gaining approval from the Institutional Review Board of Yonsei University Hospital (Registration number: 4-2015-0896), we performed a retrospective chart review for patients who had previously undergone either total hysterectomy or subtotal hysterectomy or myomectomy at the time of initial surgery for presumed benign uterine leiomyoma and were found to have uterine sarcoma on final pathology at the Department of Obstetrics and Gynecology of Yonsei University Hospital, Seoul, Korea between 2006 and 2014.

Study data were collected from patients’ medical charts: age at diagnosis, gravidity, parity, menopausal status, final pathology, stage, type of primary and secondary surgeries, date of surgery, postoperative adjuvant therapy, disease status, location of recurrence and follow-up interval. Intraoperative morcellation was introduced in our department in 2006 as a technique for extracting myomas or the uterus from the abdominal cavity during surgical management. Morcellation techniques include the use of scalpel or scissors in vaginal surgeries (hand morcellation) and a power morcellator in laparoscopy. The open morcellation techinique was performed during the study period, although the in-bag morcellation technique was adopted in 2014. Our institution has since adopted a policy of surgical re-exploration in patients with morcellated sarcoma and/or incomplete surgery, such as myomectomy or subtotal hysterectomy. The type of surgery used at re-exploration depends on each surgeon’s preferences. As a minimum, this includes the removal of the remaining uterus and exploration of the abdominal cavity. Ovarian preservation is considered in young premenopausal women with early-stage sarcomas. Stages are assigned in accordance with the 2009 FIGO staging systems.

All available hematoxylin and eosin-stained slides were reviewed by an independent gynecologic pathologist (H. S. Kim), who was blind to patient outcomes. All endometrial stromal sarcoma cases were diagnosed as low-grade endometrial stromal sarcoma based on characteristic histopathological features and uniform immunoreactivity for CD10, which is an endometrial stromal cell marker.

In this study, we compared the outcomes of uterine sarcoma found incidentally in terms of the type of initial surgery used (uterus-preserving surgery vs. hysterectomy). Despite concerns about tumor aggression in cases of uterus-preserving surgery, even without morcellation, initial uterus-preserving surgery does not appear to be associated with an adverse impact on survival outcomes for unexpected uterine sarcoma. Immediate surgical re-exploration after uterus-preserving surgery makes it possible to remove remnant sarcoma in the remaining uterus.

Myomectomy is the treatment of choice for uterine myoma when the patient wants to bear children in the future. For women who have completed childbearing, hysterectomy is typically considered to be the surgical treatment of choice for leiomyoma given the risk of recurrence after myomectomy with uterine preservation. However, many women wish to preserve the uterus even after the completion of childbearing. A US survey showed that approximately half of women aged 40–59 believed that uterine preservation was important when considering treatment options for myoma [2]. Many women express concern about the consequences of hysterectomy, including changes to function, emotions and behavior. For these women, myomectomy could be an alternative to hysterectomy, even considering the risk of recurrence or re-operation [6]. Traditional subtotal hysterectomy continues to be performed for a variety of indications, including patient preference and, in patients with challenging anatomy, surgeon preference, reflecting the technical difficulty of removing the cervix [7].

Myomectomy can be performed hysteroscopically, abdominally through a laparotomy, or, more recently, via a minimally invasive surgical approach with laparoscopic or robotic assistance. The removal of large leiomyoma through the small incisions used for minimally invasive myomectomy often poses a challenge. Large leiomyoma can be removed through a small abdominal incision, vaginally by colpotomy or through the use of power morcellation to fragment the leiomyoma. A recent Cochrane review showed that women who underwent minimally invasive surgery had significantly less blood loss, fewer incisional infections or febrile episodes, shorter hospital stays and speedier return to normal activities than those who underwent laparotomy [8]. Power morcellation plays an important role in the extraction of large leiomyoma from the abdominal cavity during minimally invasive surgery. However, following reports of poor outcomes in patients with inadvertently morcellated uterine sarcoma, the FDA has discouraged the use of laparoscopic power morcellation during hysterectomy or myomectomy for uterine fibroids.

Based on the literature, the FDA has reported that one in 352 women have unsuspected uterine sarcoma while undergoing surgery for presumed benign disease [3]. Sarcoma prevalence estimates are highly dependent on age, with the lowest prevalence among women under the age of 50 and the highest prevalence among women older than 60 [9]. As myomectomies are usually performed in the younger age group, the actual incidence of uterine sarcoma after myomectomy would appear to be lower than expected. The risk of cancer in women who undergo myomectomy performed using power morcellation is lower than that reported for hysterectomy. The prevalence of uterine cancer has been found to be 0.19 % (1 in 528) in women who undergo myomectomy without morcellation and 0.09 % (1 in 1073) in those who undergo power morcellation [10]. Therefore, in patients with unexpected uterine sarcoma after uterus-preserving surgery, tumor aggression resulting from initial surgery without power morcellation may be more common than tumor dissemination with power morcellation.

Recent National Comprehensive Cancer Network (NCCN) guidelines recommend en bloc tumor resection without tumor disruption as the standard treatment for localized sarcoma, which is consistent with the accepted management principles for soft tissue sarcoma arising in any anatomical location [11]. In uterus-preserving surgery, there may be concerns about tumor disruption associated with surgery or any remaining tumor. Therefore, patients who have undergone uterus-preserving surgery for presumed benign uterine disease and are found to have sarcoma on final pathology represent a management dilemma. However, few studies assess the prognosis for unexpected uterine sarcoma after myomectomy [4, 5].

Zhang et al. reported the outcomes of nine patients with unexpected uterine sarcoma after myomectomy [5]. Eight patients underwent a secondary operation, and endometrial stromal sarcoma was the dominant subtype of unexpected uterine sarcoma in the study. All patients were alive and there was only one case of local recurrence in the preserved ovary. Cusido et al. reported no significant difference in prognosis for uterine sarcoma in terms of myomectomy versus hysterectomy as the initial surgery [4]. Of the 14 patients who underwent myomectomy in this study, eight (57 %) underwent a secondary operation with hysterectomy. In terms of PFS, no statistical differences were found in our study. In addition, our results suggest that there may be benefits to surgical re-exploration. Of the patients who underwent re-exploration at a referral institution after myomectomy or subtotal hysterectomy, approximately 35.8 % had remnant sarcoma on the remaining uterus. However, the value of lymphadenectomy, appendectomy or omentectomy for identifying occult metastasis in early-stage uterine sarcoma appears to be low.

Regarding morcellation, our results are consistent with previous studies showing poorer outcomes with morcellation in uterine sarcoma. Concerns have been raised as uterine morcellation carries a risk of disseminating unexpected malignancy with an apparent associated increase in mortality [12]. Previous studies have shown that morcellation has a negative impact on survival outcomes in uterine sarcoma [12, 13]. Taking into consideration the negative impact of morcellation in sarcomas, this technique should be used with caution in patients with suspicious uterine sarcoma.

Initial uterus-preserving surgery does not appear to be associated with an adverse impact on survival outcomes for unexpected uterine sarcoma when surgical re-exploration is performed immediately. In our opinion, myomectomy or subtotal hysterectomy remain the preferred options for treating women with presumed leiomyoma who want to preserve the uterus as no difference in survival was found between uterus-preserving surgery and total hysterectomy, even in cases with unexpected sarcoma. Our second recommendation is that patients who undergo myomectomy or subtotal hysterectomy where uterine sarcoma is detected on final pathology undergo immediate surgical re-exploration. Surgical re-exploration appears to be useful for removing remnant sarcoma in the remaining myometrium, which is a key factor for improving outcomes in this disease subset. Further large-scale studies are required to document the outcomes of unexpected uterine sarcoma with or without morcellation after uterus-preserving surgery.