Parasitic leiomyoma in the trocar site after laparoscopic myomectomy: A case report

A 50-year-old woman was referred to our outpatient clinic, owing to the presence of a mass on the left side of the lower abdominal wall. The patient had no recent history of trauma or abdominal injuries, and did not complain of any abdominal symptoms associated with the mass. The patient had undergone laparoscopic myomectomy for uterine myoma six years ago; however, she reported no past medical, psychological, or pharmacological history. The patient could not remember any remarkable medical history of her parents or siblings. Physical examination revealed the presence of a palpable mass in the left lower quadrant, overlying the previous laparoscopic trocar site. There was no localized tenderness over the left lower quadrant. Initial laboratory tests were within normal limits as follows: white blood cell count, 3900/μL; hemoglobin level, 12.3 g/dL; and platelet count, 217000/μL. Other routine blood chemistry tests, such as renal panel, hepatic panel, pancreatic enzymes, and coagulation test were also within the normal limits. Abdominal computed tomography demonstrated a 2.2-cm well-defined contrast-enhancing mass on the left side of the abdominal wall beside the rectus muscle. There were no remarkable findings in the upper abdominal solid organ. The radiological diagnosis was a desmoid tumor, and the differential diagnosis included endometriosis and neurogenic tumors, such as neurofibroma (Figure 1 ). Abdominal computed tomography. Images of both views show a contrast-enhancing mass on the left abdominal wall (yellow arrow). A: Coronal view; B: Axial view.

The final diagnosis was a leiomyoma. Histopathological assessment after the surgery revealed that the fragment of brownish firm tissue measured 2.6 cm × 2.0 cm × 1.2 cm. Immunohistochemistry analysis for actin showed a positive result, and the final diagnosis was leiomyoma.

The patient recovered from the surgery without complications, and no other complications were observed during follow-up.

We performed surgical excision of the mass. After the skin incision, we approached the mass, which was located between the rectus muscle and aponeurosis of the external oblique muscle. The surgery took approximately 27 min from the skin incision to wound closure without intraoperative complications. The patient was discharged on the operative day without any complications.

Trocar-site implantation of a parasitic leiomyoma is a rare late complication after laparoscopic myomectomy or hysterectomy using power morcellation. Clinicians should explain to the patient the benefits and risks of the laparoscopic approach using morcellation. Moreover, efforts should be made to examine the abdominal cavity to retrieve all myoma fragments. Power morcellation during laparoscopic myomectomy should always be performed in a containment bag whenever possible to prevent excessive tissue fragmentation.

After laparoscopic myomectomy for multiple myomas with power morcellation, the patient developed trocar-site implantation of a parasitic leiomyoma without recurrence of intraperitoneal parasitic leiomyoma. Laparoscopic myomectomy and hysterectomy are increasingly used to treat gynecological tumors[ 4 ]. Power morcellators are often used to fragment bulky lesions, such as uterine myomas. Some of the small fragments may unintentionally settle in the peritoneal cavity and be implanted[ 14 ]. They receive vascular supply from the adjacent structures and develop into a parasitic leiomyoma[ 15 ]. Parasitic leiomyoma is a rare late sequala after laparoscopic myomectomy using power morcellation; the reported incidence is 0.2% to 1.25%, and diagnosis interval is four years (median)[ 8 ]. It is unclear why parasitic leiomyomas develop in only a few patients who undergo laparoscopic myomectomy or hysterectomy. A large-scale prospective study is warranted to determine the incidence and risk factors for parasitic leiomyomas after laparoscopic myomectomy or hysterectomy using power morcellation. The clinical feature of parasitic leiomyoma depends on the site of recurrence and is generally nonspecific. Parasitic leiomyomas are commonly seen in the abdominal cavity, such as small/large bowel, bladder, and vaginal stump[ 16 , 17 ]. However, to date, few cases of trocar-site implantation of a parasitic myoma after laparoscopic morcellation have been reported[ 9 - 12 ]. Most patients with trocar-site parasitic leiomyoma are asymptomatic, especially when parasitic leiomyomas are discovered incidentally during other investigations or procedures. On the other hand, in patients with symptoms, the most common symptoms are abdominal pain and a palpable mass. Measurement of tumor markers was not considered since our patient had no radiologic pelvic ascites, and the lesion was improbable to be malignant given a history of laparoscopic myomectomy. CA-125 is occasionally elevated in large parasitic leiomyomas. However, the current use of CA-125 as a biomarker for the diagnosis, differentiation and surveillance of parasitic leiomyoma is controversial and not recommended. However, if a malignancy, such as a leiomyosarcoma is suspected, measurement of tumor markers could be helpful for treatment and follow-up, especially when the level of the marker is initially elevated[ 18 ]. Treatment includes surgical resection of the parasitic leiomyoma. When the parasitic leiomyoma is in other organs, a multidisciplinary approach is recommended whenever possible. However, in this case, since the mass was located on the anterior abdominal wall of the previous trocar site, a multidisciplinary approach was not required. Thus, resection was performed by laparotomy. Power morcellation during laparoscopic myomectomy is considered a factor in the pathogenesis of iatrogenic parasitic leiomyoma[ 19 ]. In this case, parasitic leiomyoma of the abdominal wall supports this hypothesis, as the parietal peritoneum anatomically attaches to and protects the abdominal wall. During unconfined morcellation, small myoma fragments may inadvertently disperse into the abdominal cavity and regrow as parasitic leiomyomas. Morcellation should be avoided when malignancy is suspected. In 2014, the United States Food and Drug Administration (U.S. FDA) released the safety statement for laparoscopic power morcellation as follows: U.S. FDA recommended avoiding laparoscopic power morcellation for hysterectomies or myomectomies because of the risk of occult uterine sarcomas spreading[ 20 ]. Likewise, this warning should be taken seriously for benign uterine tumor removal during laparoscopic surgery. Surgeons must perform a meticulous examination to avoid tissue residue and abundant peritoneal lavage. Various alternatives have been suggested to reduce the risk of parasitic leiomyoma after laparoscopic power morcellation[ 21 ]. One of them is performing morcellation using a containment bag. This method can reduce the spread of the morcellated fragments. However, the protected manual in-bag morcellation technique is still controversial for the spread that cannot be ignored at the microscopic level[ 22 ]. Furthermore, small tissue of the myoma may be dispersed intraperitoneally during myomectomy or hysterectomy before bagging[ 23 ]. Therefore, it is necessary to cautiously examine the peritoneal cavity after laparoscopic morcellation to ensure that no small tissue fragments remain, although this approach might be incomplete for removal of all myoma fragments. Although laparoscopic surgery established better patient outcomes, care must be taken to prevent the spread of occult sarcomas, which may be closely related to survival[ 24 ].

Uterine myoma is the most common benign neoplasm of the female genitalia. However, most patients with uterine myoma are asymptomatic, despite the relatively high prevalence[ 1 , 2 ]. A variety of treatment modalities, such as medical or surgical interventions have been used for symptomatic patients. As for surgical management, laparotomy or minimally invasive surgery may be preferred[ 3 ]. Since the introduction of laparoscopic hysterectomy in 1989, several laparoscopic surgical tools have been developed to broaden the scope of minimally invasive pelvic surgery and to facilitate surgeons[ 4 ]. Several devices for laparoscopy are also used for the removal of large tumors via small incisions, enabling laparoscopic hysterectomy and laparoscopic myomectomy. The increased use of laparoscopic power morcellators has allowed the removal of large leiomyomas through small incisions with benefits, such as reduced bleeding, shorter hospital stays, and shorter recovery times[ 4 , 5 ]. Fragmentation of myoma with a morcellator can result in peritoneal dissemination, which can develop into a parasitic leiomyoma if not identified during surgery[ 1 ]. Parasitic myoma is defined as the ectopic implantation of uterine fibroids[ 6 ]. They obtain their blood supply through new blood vessels coming from adjacent organs. Since the introduction of electromechanical tissue morcellator, many studies have reported the occurrence of parasitic myomas after morcellation. This is a rare late sequela of laparoscopic morcellation procedures[ 7 ]. The prevalence of parasitic leiomyomas is estimated to be 0.07% after laparoscopically removing the uterine leiomyoma[ 8 ]. As for parasitic leiomyomas, only a few studies have reported trocar-site implantation of parasitic leiomyomas[ 9 - 12 ]. Trocar-site implantation is defined as tumor recurrence at the abdominal wall within the trocar sites, following laparoscopic examination for malignant diseases[ 13 ]. It is not metastasis but rather the occurrence of a residual tumor that has not been resected from a previous surgery. Since the pathophysiology is not clear, the disease is rare and difficult to manage. Herein, we present a case of trocar-site implantation of a parasitic myoma after laparoscopic myomectomy with power morcellation.