Iatrogenic parasitic myoma: A case report and review of the literature

A parasitic leiomyoma of the sigmoid mesentery with schwannoma-like image findings

BACKGROUND

Parasitic leiomyoma (PL) consists of uterine fibroids separate from the uterus that grow in extrauterine tissues such as the peritoneum and mesenterium. The diagnosis of PL requires a thorough medical history of laparoscopic myomectomies using a morcellator and the identification of typical magnetic resonance imaging (MRI) findings as uterine fibroids. Imaging diagnosis of PL is occasionally difficult when PL degenerates in various ways, owing to atypical findings on computed tomography (CT) and MRI.

CASE PRESENTATION

A 29-year-old woman with a history of laparoscopic myomectomy visited a local hospital with lower abdominal pain. A mesenteric tumor on the sigmoid mesentery was suspected on MRI, and she was referred to our hospital. CT scan showed strong early contrast uptake in the center of the tumor, and MRI T2-weighted images showed high signals at the tumor margins and low signals in the center, suggesting a schwannoma. PL was also part of the differential diagnosis because of the patient's history of laparoscopic myomectomy. With a preoperative diagnosis of a sigmoid colon mesenteric tumor undeniably of malignant origin, laparoscopic resection of the sigmoid mesenteric tumor was performed. Histopathological examination revealed it to be a PL.

CONCLUSIONS

We report a case of PL of the sigmoid mesentery with schwannoma-like findings on imaging that was treated laparoscopically. PL is sometimes difficult to distinguish from schwannomas because of the variety of imaging findings, such as uterine fibroids. PL should be considered in the differential diagnosis of mesenteric tumors following laparoscopic myomectomies, even if it does not show typical imaging findings, such as uterine fibroids.

Torsed retroperitoneal leiomyomas: A case report and review of literature

BACKGROUND

Retroperitoneal leiomyomas (RLs) are rare benign tumours that can occur in the pelvic and/or abdominal parietal retroperitoneum. Once torsion occurs, it causes acute abdominal pain and can even lead to serious consequences such as gangrene, peritonitis, haemoperitoneum and shock if not identified and treated promptly. Therefore, a better understanding of the characteristics of RL torsion is needed. Here, we present a case of acute pedicle torsion of an RL in the posterior peritoneum followed by a literature review.

CASE SUMMARY

Herein, we report the case of a 42-year-old woman with RL torsion. The patient visited our hospital complaining of lower abdominal pain for 6 d. Pelvic examination revealed a tender mass superior to the uterus. Pelvic magnetic resonance imaging (MRI) revealed an anterior uterine mass, multiple uterine fibroids and slight pelvic effusion. MRI suggested the possibility of a subserosal myoma of the anterior uterine wall with degeneration. Intraoperative exploration revealed a 10 cm pedunculated mass arising from the posterior peritoneum, with the pedicle torsed two times. Pathological examination confirmed a torsed RL.

CONCLUSION

In the case of a pelvic mass complicated with acute abdomen, the possibility of torsion should be considered.

Primary omental smooth muscle tumor in an adult male: a diagnostic dilemma for leiomyoma: a case report

BACKGROUND

The greater omentum comprises peritoneal, adipose, vascular, and lymphoid tissues. Most omental malignancies are metastatic tumors, and the incidence of primary tumors is rare. We report on a prior omental smooth muscle tumor case in an adult male patient.

CASE PRESENTATION

A 54-year-old Japanese male patient with no relevant medical history was diagnosed with an abdominal mass during a routine medical checkup. Subsequent contrast-enhanced computed tomography revealed a mass of approximately 3 cm in size in the greater omentum, and a laparotomy was performed. A 27 × 25 × 20 mm raised lesion was found in the omentum. Microscopically, spindle cells were observed and arranged in whorls and fascicles. Individual tumor cells had short spindle-shaped nuclei with slightly increased chromatin and were characterized by a slightly eosinophilic, spindle-shaped cytoplasm. The mitotic count was less than 1 per 50 high-power fields. The tumor cells showed positive immunoreactivity for α smooth muscle actin, HHF35, and desmin on immunohistochemical examination. The Ki-67 labeling index using the average method was 1.76% (261/14806). No immunoreactivity was observed for any of the other tested markers. We considered leiomyoma owing to a lack of malignant findings. However, primary omental leiomyoma has rarely been reported, and it can be difficult to completely rule out the malignant potential of smooth muscle tumors in soft tissues. Our patient was decisively diagnosed with a primary omental smooth muscle tumor considering leiomyoma. Consequently, the patient did not undergo additional adjuvant therapy and was followed up. The patient was satisfied with treatment and showed neither recurrence nor metastasis at the 13-month postoperative follow-up.

DISCUSSION AND CONCLUSION

We encountered a primary smooth muscle tumor of the greater omentum with no histological findings suggestive of malignancy in an adult male patient. However, omental smooth muscle tumors are extremely difficult to define as benign, requiring careful diagnosis. Further case reports with long-term follow-up and case series are required to determine whether a true omental benign smooth muscle tumor (leiomyoma) exists. In addition, proper interpretation of the Ki-67 labeling index should be established. This case study is a foundation for future research.

Case report Iatrogenic parasitic leiomyoma: the surgeon's invisible hand

Uterine leiomyoma is the most common benign tumour of the uterus in women of reproductive age. When removed surgically, a mini-invasive procedure is preferentially used (laparoscopic or robotic) and the extraction of the specimen can be managed by power morcellation. In this consecutive case-series, we present three cases of parasitic leiomyoma that appeared following previous surgical management of leiomyoma using the technique of laparoscopic myomectomy with uncontained power morcellation. The time frame in between the initial surgery and the diagnosis of the parasitic leiomyoma was 5.7 years. All three patients were diagnosed with endometriosis: 2 cases prior to the initial surgery and 1 case after the initial surgery. One hypothesis could be that, due to pelvic inflammation, endometriosis is a risk factor for iatrogenic parasitic leiomyoma development in case of uncontained morcellation of leiomyoma during myomectomy.

Parasitic Leiomyoma with Lymphatic Dilatation in Trocar Port-Site of Abdominal Wall: A Case Report

Uterine leiomyoma is the most common benign pelvic tumor in female and being symptomatic is an indication for surgical removal. As laparoscopic surgery has been developed, some cases related to parasitic leiomyomas in the port site have been reported. A 40-year-old female who a history of previous laparoscopic surgery to remove uterine myoma 2 years ago visited in outpatient clinic of general surgery with palpable mass in left lower abdomen. Contrast enhanced abdomen CT and pelvis MRI were done to evaluate the mass. It was diagnosed parasitic leiomyoma in pathologic study after surgical removal and parasitic leiomyoma should be considered when patient visited presenting abdominal mass with the history of laparoscopic myomectomy.

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

BACKGROUND

Laparoscopic myomectomy is increasingly used for resecting gynecological tumors. Leiomyomas require morcellation for retrieval from the peritoneal cavity. However, morcellated fragments may implant on the peritoneal cavity during retrieval. These fragments may receive a new blood supply from an adjacent structure and develop into parasitic leiomyomas. Parasitic leiomyomas can occur spontaneously or iatrogenically; however, trocar-site implantation is an iatrogenic complication of laparoscopic uterine surgery. We describe a parasitic leiomyoma in the trocar-site after laparoscopic myomectomy with power morcellation.

CASE SUMMARY

A 50-year-old woman presented with a palpable abdominal mass without significant medical history. The patient had no related symptoms, such as abdominal pain. Computed tomography findings revealed a well-defined contrast-enhancing mass measuring 2.2 cm, and located on the trocar site of the left abdominal wall. She had undergone laparoscopic removal of uterine fibroids with power morcellation six years ago. The differential diagnosis included endometriosis and neurogenic tumors, such as neurofibroma. The radiologic diagnosis was a desmoid tumor, and surgical excision of the mass on the abdominal wall was successfully performed. The patient recovered from the surgery without complications. Histopathological examination revealed that the specimen resected from the trocar site was a uterine leiomyoma.

CONCLUSION

Clinicians should consider the risks and benefits of laparoscopic vs laparotomic myomectomy for gynecological tumors. Considerable caution must be exercised for morcellation to avoid excessive tissue fragmentation.

Metastatic Smooth Muscle Tumor of Uncertain Malignant Potential after Laparoscopic Presuming Myomectomy

A 38-year-old para-2 female underwent laparoscopic myomectomy with uncontained morcellation. Three years later, she complained of epigastric pain. An intraperitoneal 3 cm mass beneath the umbilicus was showed on computed tomography (CT) scan. With the impression of gastrointestinal stromal tumor, she underwent open laparotomy at the general surgery department. A tumor was excised. Pathological examination showed that the tumor was consistent with a smooth muscle tumor of uncertain malignant potential smooth muscle tumors of uncertain malignant (STUMP). Six years postlaparoscopic myomectomy, during a regular follow-up, three parauterine masses were found on ultrasonography and CT scan. She underwent laparoscopic surgery for hysterectomy, bilateral salpingectomy, and excision of the masses. The masses were again diagnosed as STUMP. This case presents a recurrence of a rare type of smooth muscle tumor after uncontained morcellation. If myomas are to be removed with morcellation, it should only be used appropriately with a compatible containment system, and the risk of occult malignancy should be counseled.

Iatrogenic Port Site Parasitic Myoma; Case Report and Literature Review

Introduction

We report a case of iatrogenic parasitic myoma of the anterior abdominal wall and discuss the differential diagnosis, treatment, and prevention of complication with relevant literature.

Case Report

A 33-year-old woman presented with anterior abdominal wall mass 3 years after initial laparoscopic myomectomy surgery. A mass with a 38 × 26 mm diameter was observed in the anterior abdominal wall at the site of inferior left side port of previous surgery. It was excised from the anterior abdominal wall outside of the peritoneum, below the fascia. The pathologic examination of the excised mass revealed cellular myoma. This case is the 4th port site parasitic myoma in literature.

Conclusion

The risk of implantation and subsequent growth of minute myoma fragments should be kept in mind during morcellation procedures and, in order to avoid such complications, all fragments should be tracked during morcellation. The inspection of trocar sites after the removal of trocars for retained fragments would prevent such recurrences.

Safety of Minimally Invasive Tissue Extraction in Myoma Management: A Systematic Review

OBJECTIVE

This review seeks to establish the incidence of adverse outcomes associated with minimally invasive tissue extraction at the time of surgical procedures for myomas.

DATA SOURCES

Articles published in the following databases without date restrictions: PubMed, EMBASE, Web of Science, Cochrane Database of Systematic Reviews and Trials. Search was conducted on March 25, 2020.

METHODS OF STUDY SELECTION

Included studies evaluated minimally invasive surgical procedures for uterine myomas involving morcellation. This review did not consider studies of nonuterine tissue morcellation, studies involving uterine procedures other than hysterectomy or myomectomy, studies involving morcellation of known malignancies, nor studies concerning hysteroscopic myomectomy. A total of 695 studies were reviewed, with 185 studies included for analysis.

TABULATION, INTEGRATION, AND RESULTS

The following variables were extracted: patient demographics, study type, morcellation technique, and adverse outcome category. Adverse outcomes included prolonged operative time, morcellation time, blood loss, direct injury from a morcellator, dissemination of tissue (benign or malignant), and disruption of the pathologic specimen.

CONCLUSION

Complications related to morcellation are rare; however, there is a great need for higher quality studies to evaluate associated adverse outcomes.

Iatrogenic Parasitic Myoma with Two Recurrence Times after Subsequent Myomectomy: A Rare and Complicated Case Report

Increasing number of parasitic myoma (PM) cases due to specimen morcellation during minimally invasive surgery have been reported. The patient was a 46-year-old woman receiving laparoscopic subtotal hysterectomy due to fibroids. She was diagnosed as having PM and had two recurrences after subsequent myomectomies. To prevent recurrence, specimen-contained morcellation was performed during the myomectomies and postoperative ulipristal acetate was given, but with no effects. The interval between each recurrence decreased. Progressive lower abdominal pain and prominent vessels on the myoma were the two distinct clinical characteristics that differentiated PM from general myoma. This case study highlights the importance of specimen containment before morcellation in minimally invasive surgery and implies that the pathogenesis of PM recurrence is unknown.

Port site parasitic leiomyoma after laparoscopic myomectomy: a case report and review of the literature

Background

Uterine fibroids are the commonest benign gynecological tumors. Laparoscopic myomectomy is becoming increasingly popular as one of the surgical treatment options for symptomatic cases. Large tissues such as leiomyomas or even the uterus need to be morcellated in order to be retrieved from the abdominal cavity. Some of the morcellated fragments or small fibroids may be accidentally left in the abdominal cavity during the retrieval process. These may subsequently become implanted in the abdominal cavity, develop blood supply from the surrounding structures, and grow to form parasitic myomas with varied clinical presentation, depending on the location and size.

Case presentation

A 47-year-old African woman presented to our hospital 6 years after laparoscopic myomectomy with a lower abdominal mass. Her work-up revealed an anterior abdominal wall mass consistent with uterine leiomyoma. She was scheduled for excision of the mass, which was subsequently histologically confirmed to be a uterine fibroid.

Conclusions

Parasitic leiomyomas are a rare late complication of power morcellation following laparoscopic myomectomy or hysterectomy. Most patients present with an abdominal/pelvic mass and may need surgical excision to relieve the symptoms. Care should be taken during power morcellation to prevent excessive fragmentation of the tissues, some of which may become implanted and persist to form parasitic myomas. Moreover, effort should be made to retrieve all myoma fragments by carefully checking the abdominal cavity. Whenever possible, the morcellation should be done in a containment bag.

Reducing the spread of occult uterine sarcoma at the time of minimally invasive gynecologic surgery

PURPOSE

This review covers the most recent evidence to discuss the incidence of occult uterine sarcoma, whether morcellation increases tumor dissemination or mortality, and whether there is a difference between different types of morcellation. We will also discuss techniques to reduce the spread of an undiagnosed uterine sarcoma.

METHOD

A comprehensive literature search was made in Pubmed, Medline, the Cochrane Library, and Google Scholar for articles related to the incidence of occult uterine sarcoma after morcellation.

RESULTS

Fibroids are benign uterine tumors and are a common indication for gynecologic surgery. Increasingly, gynecologists are approaching these surgeries with minimally invasive techniques. Uterine sarcomas are rare malignant mesenchymal tumors that are difficult to distinguish preoperatively from uterine fibroids.

CONCLUSION

During a minimally invasive surgery, there is a risk of disseminating an occult sarcoma during tissue extraction. Minimally invasive gynecologists are tasked with balancing taking a minimally invasive approach, which is shown to result in better patient outcomes, with minimizing the risk of spreading an occult sarcoma.

Oestrogen-induced angiogenesis and implantation contribute to the development of parasitic myomas after laparoscopic morcellation

BACKGROUND

Iatrogenic parasitic myomas (PMs), caused by intra-corporeal power morcellation during laparoscopy is gradually increasing. However, the pathogenesis and medical treatment of PMs remain largely unelucidated.

METHODS

Laparoscopically-induced PM xenografted mouse model was conducted by xenografting human uterine myoma fragments into the abdominal cavity of SCID mice and hormonal manipulation was performed using this mouse model to demonstrate the role of oestrogen in the development of implanted PMs. Immunohistochemistry of oestrogen receptor α (ERα), progesterone receptor (PR), vimentin, vascular endothelial growth factor (VEGF), microvessel density (MVD) and Ki-67 index was performed and compared.

RESULTS

In the patient with PMs, ERα, PR, angiogenesis and proliferative property expression were upregulated in PM lesions compared to uterine myomas. In the laparoscopically-induced PM mouse model, implanted myomas had more steroid receptor expressions, angiogenesis and proliferative property compared with pre-xenografted or non-implanted myoma. Depletion of oestrogen in the ovariectomized (OVX) mice decreased laparoscopically-induced PM implantations. In comparison, the implantations of PMs were increased with additional E2 supplement. Hormonal manipulation in the PM mouse model, including AI, GnRHa and SERM groups, were compared and AI significantly decreased the implantations, steroid receptor, angiogenesis, cell density, and proliferative index of PMs compared with control group. Furthermore, GnRHa significantly decreased VEGF and MVD expressions compared with control group.

CONCLUSIONS

These data highlight the crucial role of oestrogen in the development of laparoscopically-induced PMs and suggest that hormone manipulation may be a potential therapeutic agent.

TRIAL REGISTRATION

This protocol was approved by the Human and Animal Institutional Review Board of Taipei Veterans General Hospital ( VGHIRB No 2014-10-002C on Nov. 17^th, 2014; IACUC 2014-119 on Aug. 22^nd, 2014).

Parasitic leiomyomas: a systematic review

BACKGROUND

Parasitic leiomyomas were first described as early as 1909 but are a rare condition. In recent years, due to the rise of laparoscopic surgery and power morcellation, several cases of parasitic leiomyomas associated with this surgical procedure have been reported.

METHODS

A literature search was performed using PubMed, Embase and Google Scholar with the following combination of keywords: leiomyoma OR uterine neoplasms OR uterine myomectomy OR laparoscopy OR hysterectomy OR peritoneal neoplasms AND parasitic. Papers describing parasitic leiomyomas were included. The results of these studies are summarized herein.

RESULTS

We retrieved abstracts of 756 papers. Of these, 591 were excluded for not fulfilling the inclusion criteria and 54 were removed as duplicates; after full-text assessment, 8 were rejected for presenting cases of malignancy and finally 103 were included in our systematic review. From these, we present information about 274 patients with parasitic leiomyomas. The mean age of women was 40 years (range 18-79 years); and 154 (56%) had no history of uterine surgery, the others (120, 44%) having had a previous myomectomy or hysterectomy. Of the total, 106 (39%) women had a history of power morcellation. The most frequent clinical symptom was abdominal pain (49%) and the most frequent presentation was disseminated peritoneal leiomyomatosis.

CONCLUSIONS

While parasitic leiomyoma was first described a century ago, the recent introduction of laparoscopic power morcellation has increased the number of reported cases.

Torsion of a parasitic myoma that developed after abdominal myomectomy

Iatrogenic parasitic myomas are rare. The condition is defined by the presence of multiple smooth-muscle tumorous nodules in the peritoneal cavity. This may be attributable to seeding of myoma particles during uterine surgery. The clinical course is usually indolent. The disease is often asymptomatic and is usually discovered only incidentally. A 38-year-old woman who had undergone abdominal myomectomy 7 months prior presented with acute abdominal pain and a huge pelvic mass. We performed exploratory laparotomy. A parasitic mass 17 cm in diameter with a twisted omental pedicle was identified. En bloc excision of the mass and omentum was performed, followed by total abdominal hysterectomy. Histopathological examination of multiple sections revealed features compatible with an infarcted leiomyoma. Thus, we present a very rare case of an iatrogenic, rapidly growing parasitic myoma complicated by omental torsion (which caused the acute abdominal pain). We also offer a literature review.

Risk, risk reduction and management of occult malignancy diagnosed after uterine morcellation: a commentary

Minimally invasive surgical techniques compared with laparotomy offer the advantages of less intraoperative blood loss, shorter hospitalization, fewer wound complications and faster return to baseline activity for both hysterectomy and myomectomy. While morcellation allows for the laparoscopic removal of large specimens, it may result in intraperitoneal dissemination of benign disease or upstaging of occult malignancy leading to compromised survival. There has been heightened scrutiny over appropriate patient selection and preoperative assessment in light of recent warnings against power morcellation issued by the US FDA. This commentary therefore summarizes the magnitude of such risks associated with uterine morcellation, current national regulatory statements and potential merits of risk-reducing approaches such as contained morcellation. The importance of patient counseling is underscored.

Imaging techniques for evaluation of uterine myomas

Due to their high prevalence and related morbidity, uterine myomas constitute a group of gynecological pathologies largely studied in all clinical, diagnostic, and therapeutic aspects. They have been widely evaluated with a large series of imaging techniques. In fact, ultrasound (also saline infusion sonohysterography) and magnetic resonance imaging (MRI) are considered the optimal methods to assess uterine fibroids in terms of number, volume, echostructure, location, relation with endometrial cavity and uterine layers, vascularization, and differential diagnosis with other benign (adenomyosis) and malignant myometrial pathologies. Nevertheless, further studies are required to fill some gaps such as the absence of a common and sharable sonographic terminology and methodology to scan the myometrium, as well as imaging parameters for differentiation of typical myomas from smooth tumors of unknown malignant potential (STUMP) and leiomyosarcomas.

Parasitic myoma after laparoscopic surgery: a mini-review

The aim of this review is to summarize the cases of parasitic myomas after laparoscopic surgery. A literature search was performed using the PubMed database for the period of January 1997 to December 2014. We used the following keywords: "laparoscopic hysterectomy," "laparoscopic myomectomy," "morcellation," "parasitic fibroids," "parasitic myomas," and "leiomyomatosis." A total of 29 articles meeting the selection criteria were included in our review, describing 53 patients who underwent surgery for parasitic myomas. Parasitic myoma is a rare condition resulting from the small fibroid fragments left after morcellation and can be either asymptomatic or symptomatic. Although it is rare, patients should be informed about the risk of this condition after laparoscopic surgery. It is important for surgeons to look for small fibroid fragments during and after morcellation and make an effort to remove every piece of tissue.