Rare Presentation of Parasitic Leiomyomata in the Fallopian Tube and Ovarian Ligament: Clinical, histopathologic, and imaging insights

In 2025, a 30-year-old female patient, married for 2 years, presented to Al Emadi Hospital in Doha, Qatar with progressive chronic pelvic pain, heaviness, and congestive dysmenorrhoea. She also reported recurrent acute episodes of sharp right-sided pelvic pain accompanied by fainting and occasional nausea. These episodes occurred frequently during sexual intercourse and often necessitated visits to the emergency department, where she received symptomatic treatment. She was not seeking fertility. Vaginal examination revealed fullness in the right and posterior fornices with associated tenderness. Transabdominal and transvaginal ultrasonography demonstrated multiple uterine leiomyomata without evidence of degeneration, including at least four large subserosal and several smaller intramural lesions. Doppler evaluation of the large right-sided leiomyoma (8 × 6 cm) showed preserved arterial blood flow with increased peak systolic velocity, low impedance flow (as indicated by pulsatility index, resistance index, and impedance index), and a normal systolic–diastolic ratio. Owing to the unexplained sharp pain, contrast-enhanced magnetic resonance imaging (MRI) was performed, which confirmed multiple non-degenerate leiomyomata. These appeared hypointense on T2-weighted imaging and isointense on T1-weighted imaging. MRI also revealed a large extra-myometrial mass located to the right and posterior to the uterus in the presacral space, with a connecting pedicle suggestive of an FT leiomyoma. Adjacent to this, a smaller mass was connected to the uterus through a delicate stalk but not to the myometrium, raising suspicion of an OL leiomyoma [ Fig. 1 ]. Parasitic leiomyomata on magnetic resonance imaging with contrast. A: Sagittal T2-weighted image showing the uterus with multiple anterior and posterior leiomyomata. A large mass is present posterior to the uterus in the presacral space, connected by a pedicle consistent with a fallopian tube leiomyoma. Proximal to this, a smaller mass is attached to the uterus by a fine stalk, consistent with an ovarian ligament leiomyoma. B: Coronal T1-weighted fat-saturated contrast-enhanced image demonstrating the same findings. A third mass is visible on the left side, connected to the myometrium, consistent with a left subserosal leiomyoma. The possibility of parasitic leiomyomata was discussed with the patient and her spouse, and consent was obtained for open myomectomy with the option of right salpingectomy if the FT was found to be non-functional or damaged. Following approval from the Institutional Review Board and insurance provider authorisation, the patient underwent preoperative assessment by the anaesthesia team and was scheduled for surgery. Under general anaesthesia, a Pfannenstiel mini-laparotomy incision was made, and the uterus was exteriorised using uterine holding forceps with counter-traction to facilitate extraction. In addition to multiple intramural and subserosal leiomyomata, two parasitic leiomyomata were identified: a large right FT leiomyoma and a smaller right OL leiomyoma [ Fig. 2 A]. Intraoperative findings. A: Large right fallopian tube (FT) and smaller right ovarian ligament (OL) leiomyoma. B: The site of excised right fallopian tube and ovarian ligament leiomyomata (OL). Myomectomy was performed using a fertility-preserving technique with meticulous haemostasis, multilayer closure of the hysterotomy incision, and the use of fine sutures, while avoiding exposure of raw edges to reduce adhesion formation. The FT leiomyoma was excised through a circumferential incision 1 cm distal to the affected segment to avoid injury to the tubal lumen. The musculature of the FT was then reconstructed with fine 3-0 Monocryl sutures. The OL leiomyoma was excised in a similar manner, and the ligament was repaired. Following complete excision of the leiomyomata [ Fig. 2 B], peritoneal lavage was performed, adhesion-preventive sheets were placed, and an intraperitoneal drain was inserted. The drain was removed the following morning, and the patient was discharged after an uneventful postoperative course, following a course of broad-spectrum antibiotics. Macroscopic histopathological assessment of the specimens demonstrated typical leiomyomatous features, with uniform smooth muscle cells arranged in whorled anastomosing fascicles interspersed with fibrovascular tissue, stained with haematoxylin and eosin at ×40 magnification [ Fig. 3 ]. Histopathological findings. A: Gross appearance of leiomyomata (fallopian tube and ovarian ligament). B: Microscopic examination of the fallopian tube leiomyoma showing uniform smooth muscle cells arranged in whorled anastomosing fascicles interspersed with fibrovascular tissue, stained with haematoxylin and eosin at ×40 magnification. At six-month follow-up, the patient reported marked improvement in symptoms and expressed satisfaction with the outcome.

Parasitic or ectopic leiomyomas are rarely reported in the literature. Iatrogenic parasitic leiomyomas are believed to be more commonly encountered due to the widespread use of laparoscopic myomectomy, in which small fragments of leiomyoma tissue may remain if mechanical or open power morcellation is performed. This concern led the United States Food and Drug Administration (FDA) in February 2020 to prohibit open morcellation and to recommend the use of a closed tissue containment system in all cases of laparoscopic power morcellation in order to prevent parasitic leiomyomas and to reduce the risk of disseminating occult leiomyosarcoma. 2 Although extremely rare, fallopian tube leiomyomas are thought to arise either from the smooth muscle of the tube or from vascular smooth muscle cells within its blood supply. 3 Given that the fallopian tube develops embryologically from the Müllerian duct, there is a logical basis for the development of leiomyomas in this location. A possible occurrence of parasitic leiomyoma of the ovarian ligament has been mentioned previously but without confirmatory evidence. 4 To the best of current knowledge, this is the first documented case of a parasitic leiomyoma arising from the ovarian ligament. The distinction between fallopian tube and ovarian ligament leiomyomata lies in their tissue of origin. A leiomyoma arising from the fallopian tube is considered parasitic because it develops from the muscularis layer of the tube, which contains smooth muscle tissue. In contrast, the ovarian ligament is primarily a fibrous structure derived from the endopelvic fascia and does not contain an inherent muscular layer, making it unlikely for a leiomyoma to originate there through normal smooth muscle proliferation. Therefore, the most plausible explanation for the occurrence of a leiomyoma in the ovarian ligament is metaplasia, specifically the transformation of fibrous tissue into smooth muscle, supporting a metaplastic origin theory. This hypothesis suggests that mesenchymal stem cell metaplasia, potentially triggered by hormonal or genetic factors, may account for such development. 4 Histopathological similarities between the parasitic leiomyomas of the fallopian tube, ovarian ligament, and uterus in this case further strengthen this explanation. The clinical presentation in this patient was consistent with fallopian tube leiomyomas, characterised by chronic pelvic pain due to the heaviness associated with both uterine and parasitic leiomyomata, along with intermittent acute right-sided visceral pain. These acute pain episodes were accompanied by fainting and nausea during movement or sexual activity, which raised suspicion of torsion of either a subserosal uterine or parasitic fallopian tube leiomyoma, a possibility supported by vaginal examination findings. The acute visceral pain was likely related to involvement of fallopian tube innervation, provoked by sudden movement. 5 The preserved arterial blood flow observed on Doppler imaging in this patient with acute abdominal pain makes the presence of a gangrenous twisted leiomyoma unlikely. Torsion initially impairs venous drainage while preserving arterial supply, leading to congestion and swelling. Advanced torsion can subsequently obstruct arterial flow and result in gangrenous transformation. These features highlight the value of integrated imaging modalities, such as transvaginal ultrasonography and Doppler evaluation, in assessing patients with multiple leiomyomata located at different pelvic sites. Differentiating between fallopian tube leiomyomas and non-twisted subserosal leiomyomas is challenging, even with magnetic resonance imaging, because the narrow calibre of the normal fallopian tube complicates visualisation and its close proximity to the uterine cornual end makes delineation difficult. Fallopian tube leiomyomas are frequently misinterpreted as subserosal leiomyomas with a slender pedicle, and the same diagnostic difficulty applies to ovarian ligament leiomyomas. To improve diagnostic accuracy, intrauterine fluid instillation can be used to visualise the fallopian tubes and distinguish fallopian tube leiomyomas from pedunculated non-twisted subserosal leiomyomas. A previous study employed magnetic resonance hysterosalpingography with semiquantitative dynamic contrast-enhanced perfusion following intrauterine injection of a diluted gadodiamide and saline mixture to evaluate fallopian tube patency. 6 Most previously published case reports of fallopian tube leiomyomata describe them as incidental intraoperative findings. 1 In contrast, the current case was notable in that the preoperative clinical features of recurrent acute exacerbations of chronic pelvic pain, combined with Doppler findings and magnetic resonance imaging, raised suspicion of both uterine and extrauterine leiomyomata, which was subsequently confirmed intraoperatively. A comprehensive preoperative workup in all cases of multiple leiomyomata is essential to assess their anatomical relationships with pelvic organs, particularly the ureters, to exclude concurrent endometriosis and to determine the most suitable surgical strategy. 4 Additional operative procedures should be discussed with the patient and consented to prior to surgery, as in this case where consent for possible salpingectomy was obtained. In terms of surgical approach, a mini-laparotomy was selected as the most appropriate option given the presence of multiple leiomyomata of varying size and anatomical location [ Fig. 2 ]. Awareness of parasitic leiomyomas before surgery is crucial for fertility preservation. In this case, a delicate circumferential incision was made at least 1 cm distal to the base of the fallopian tube lesion, followed by microsurgical suturing to preserve tubal functionality. An incision along the long axis of the large fallopian tube leiomyoma was avoided, as peeling the lesion through such an approach would have resulted in extensive bleeding from a large raw surface and increased the risk of adhesion formation.

Parasitic leiomyomata should be considered whenever a leiomyoma is identified separately from the myometrium on imaging. Diagnosis should be based on the integration of clinical features, Doppler ultrasonography, and supportive magnetic resonance imaging findings. Although exceptionally rare, fallopian tube leiomyomas must be included in the differential diagnosis of acute exacerbations of chronic pelvic pain in patients with solid adnexal masses, particularly when such masses are palpable vaginally or visualised on imaging as distinct from the uterus. To the best of current knowledge, this represents the first documented case of a parasitic leiomyoma of the ovarian ligament, supporting metaplasia as its likely origin. The absence of comprehensive epidemiological data on parasitic leiomyomata of the fallopian tube and ovarian ligament highlights the importance of publishing additional case reports and series to improve physician awareness of these rare entities.

Extra-myometrial (parasitic or ectopic) leiomyomas are classified as type 8 under the International Federation of Gynaecology and Obstetrics (FIGO) classification of leiomyomata. These tumours may occur in the broad ligament, ovary, cervix, abdominal wall, and other rare sites in patients with uterine leiomyomata. 1 Despite the high prevalence of uterine leiomyomas, the true prevalence of parasitic leiomyomas remains uncertain due to their rarity and the limited number of published case reports. 1 This case highlights the clinical presentation, preoperative imaging findings, surgical management, and histopathological assessment of the exceptionally rare parasitic leiomyomata of the fallopian tube (FT) and ovarian ligament (OL).

Patient has signed a consent form to allow publication of her case anonymously.

Atef Darwish: Conceptualization, surgical management, Software, Data curation, Writing- Original draft preparation. Dina Darwish: review the manuscript. Shatha Ali: performed radiologic diagnosis. Amani Omar: performed histopathologic assessment.

We sincerely thank the patient for providing consent and allowing us to share her case for educational purposes.

Data is available upon reasonable request from the corresponding author.