Parasitic Leiomyoma at Laparoscopic Trocar Site: A Report of 2 Cases

Introduction

Parasitic leiomyoma was first described by Willson and Peale in 1952 and was named by Taubert in 1965 [1,2]. Parasitic leiomyoma refers to the leiomyoma found at extrauterine sites [3–5]. Lu et al estimated that the prevalence of iatrogenic parasitic leiomyoma was 0.07% [6]. Most patients initially have no symptoms, and with the progression of the disease, some patients presented abdominal pain and abdominal distension [7–9]. Usually, parasitic leiomyoma is a benign disease, and almost all patients have a good prognosis [10,11]. Currently, morcellators is believed to be the main cause of iatrogenic parasitic leiomyoma, which is used to crush leiomyomas and can generate leiomyoma fragments [7–9].

Here, we report 2 cases of parasitic leiomyomas at trocar sites and describe their diagnosis, imaging characteristics, and clinical management.

Case Reports

CASE 1:

A 47-year-old woman (para 1-0-2-1) underwent laparoscopic total hysterectomy 4 years ago due to uterine multiple leiomyoma and cervical intraepithelial neoplasia II. The patient discovered abdominal and pelvic masses and thus came to our hospital. She had regular menstruation, and no relevant medical history. Physical examination revealed a mass at the upper edge of the vaginal stump, and 2 masses at the left trocar site (one with a diameter of approximately 2.5 cm and the other with a diameter of approximately 1.0 cm). Blood potassium was low, and potassium supplementation treatment was given. No other specific findings were detected on general examination.

B-ultrasound showed the vaginal stump, and 2 uneven low echoes were found in the pelvic cavity, measuring 5.2×5.1×3.7 cm and 2.5×2.0×2.4 cm (Figure 1A, 1B).

Pelvic enhanced magnetic resonance imaging (MRI) indicated that the vaginal stump was visible, 2 masses were seen above the vaginal stump, measuring 4.2×4.1×4.3 cm and 2.5×2.0×2.5 cm.

Based on the physical examination, B-ultrasound, and MRI, the patient was clinically diagnosed as having a pelvic mass, abdominal wall mass, and post-hysterectomy status.

During laparoscopy, 2 myomatous nodules were found 0.5 cm from the left trocar site, which were located between the fat layer and fascia layer (Figure 2A, 2B). Three myomatous nodules were found near the rectum in the lower part of the sigmoid colon, with abundant blood supply (Figure 2C, 2D). The diameters of the 3 myomatous nodules were 5.0 cm, 2.5 cm, and 1.0 cm. A mass was found on the right pelvic wall, which had a thin wall and clear internal fluid, with a diameter of about 1.0 cm. Three myomatous nodules on the surface of the sigmoid colon and pelvic wall mass were removed laparoscopically and 2 myomatous nodules at the left trocar site were removed through laparoscopy and skin incision.

Pathology reported that the abdominal wall mass was multiple leiomyoma, and the intestinal mass was multiple leiomyoma with abundant cells. The pelvic mass was fibrous capsule wall tissue, partially lined with simple squamous epithelium. This patient was discharged 4 days after the operation, and received 3 months of GnRH-a treatment. She was followed up for 9 months, and no recurrence has been detected so far.

CASE 2:

A 50-year-old woman (para 1-0-0-1) was admitted to the Department of Gynecology with a concern of abdominal masses. Fifteen years ago, she underwent laparoscopic removal of the right ovarian cyst. Two years ago, she found a mass on the trocar site of the right abdominal wall. She had regular menses and no relevant medical history. At admission, physical examination revealed an enlarged uterus and a palpable mass of about 5×5×2 cm on the trocar site of the right abdominal wall, with unclear boundary. No other specific findings were detected on general examination.

B-ultrasound demonstrated that there were multiple hypoechogenic masses in the right lower abdominal muscle layer (the larger 2 were 4.6×1.3×3.2 cm and 4.4×2.4×1.6 cm, Figure 3A, 3B), and showed multiple hypoechogenic masses in the uterus (the largest was 6.3×5.7×4.6 cm, Figure 4A, 4B). Based on the above examination results, the patient was clinically diagnosed as having uterine leiomyoma and parasitic leiomyoma.

The patient underwent transabdominal total hysterectomy, bilateral fallopian tube resection, and abdominal wall lesion resection. After removal of the uterus and both fallopian tubes, the peritoneal tissue on the surface of the myomatous nodules was incised on the medial side of the right trocar site, and some myomatous nodules were found, which were about 4×3×3 cm in size and formed by the fusion of 4 nodules. The adipose layer tissue above the remaining myomatous nodules was incised on the surface skin of the right trocar site, and the wound was deep into the muscle layer. The remaining myomatous nodules were fused with multiple nodules, with a bead-like surface and a size of about 3×2×2 cm (Figure 5). All the myomatous nodules were totally removed (Figure 6A, 6B).

The myomatous nodules at the right trocar site were sent for intraoperative rapid freezing pathology and the result showed parasitic leiomyoma of peritoneum. The final pathological report showed multiple leiomyomas of the uterus (one of which was a cell-rich leiomyoma), and the cell-rich parasitic leiomyoma at right trocar site with unclear boundary. Immunohistochemistry showed P53 (−), ER (+), Desmin (+), Ki-67 (5%+), P16 (−), and SMA (+).

The patient was discharged 7 days after surgery, without any complications. At the Outpatient Department, the patient received 3 cycles of GnRH-a to avoid recurrence. The patient was followed up for 6 months, and no recurrence has been detected so far.

Discussion

Parasitic leiomyoma is a rare disease, and the most common locations are the peritoneal cavity, mesentery, greater omentum, ovary, fallopian tube, intestinal tube, and the serous surface of the bladder [3]. Currently, morcellators, which can crush leiomyomas in laparoscopy, are regarded as the main cause of iatrogenic parasitic leiomyoma. Parasitic leiomyoma lacks typical clinical symptoms, which are related to its location and size. Therefore, the diagnosis of parasitic leiomyoma is difficult, and imaging plays an important role in diagnosis.

In our review of the literature, we found only 6 documents reporting parasitic leiomyoma at trocar sites [4,5,7,8,12,13]. Patients’ ages ranged from 26 to 50 years old, and they all underwent surgery to remove parasitic leiomyomas after diagnosis (Table 1). Furthermore, all the patients underwent laparoscopic myomectomy and morcellation, and parasitic leiomyomas were found at trocar sites at 2 months to 6 years after surgery. The main diagnostic imaging method is B-ultrasound, followed by MRI and CT. Parasitic leiomyoma is easy to miss, and imaging can mislead clinicians in making a diagnosis, especially B-ultrasound. In summary, the B-ultrasound findings display hypoechoic masses with clear boundaries, similar to uterine leiomyoma. The literature suggests that morcellation should be conducted within a sealed bag, then a thorough cleaning of the abdominal cavity is needed to avoid implantation of any residual leiomyoma. Equally important, it is recommended to protect the edges of the surgical wound to avoid parasitic leiomyoma.

There is no consensus on the optimal treatment for parasitic leiomyoma. Surgery is usually the preferred treatment, and GnRH-α may be recommended, depending on the patient’s condition. All patients reported in the literature underwent surgery to remove parasitic leiomyomas (Table 1). Chen et al reported the case of a 26-year-old patient with parasitic leiomyoma [12]. After receiving surgery and GnRH-α, this patient became pregnant and gave birth, and no parasitic leiomyomas were found during cesarean section. The 2 patients that we report had regular menses; therefore, to reduce the risk of recurrence, they underwent 3 months of GnRH-α after surgery, and they are currently free of recurrence.

Conclusions

We report 2 rare cases of parasitic leiomyoma at laparoscopic trocar sites. When a patient finds an unexplained pelvic mass after laparoscopy, the differential diagnosis of parasitic leiomyoma should be considered, regardless of whether myomectomy or morcellation were performed. Imaging findings, especially B-ultrasound, provide vital information for clinical diagnosis and differential diagnosis.