Clinicopathological characteristics and etiological considerations of isolated fallopian tube torsion in pediatric patients: a single center study

Introduction

Isolated fallopian tube torsion (IFTT) is an exceptionally rare etiology of acute abdominal pain in pediatric female patients. In the absence of timely diagnosis and surgical intervention, disease progression may result in tubal necrosis, frequently necessitating salpingectomy and increasing the risk of subsequent subfertility (1,2). While the incidence of IFTT has historically been estimated at approximately 1 in 1,500,000 (3), its true prevalence in the pediatric population remains uncertain due to the limited number of reported cases (4).

Although the pathogenesis of IFTT is not fully elucidated, several predisposing factors have been identified and are broadly classified as intrinsic or extrinsic (2,5). Intrinsic factors include congenital or acquired anomalies such as elongation of the fallopian tube or mesosalpinx, hematosalpinx, hydrosalpinx, tubal neoplasms, aberrant peristalsis, and venous congestion of the mesosalpinx (5,6). Extrinsic contributors may involve adjacent anatomical structures and include ovarian or para-tubal cysts, postoperative adhesions, infections, neoplasms, and abdominal trauma (7,8). Additionally, Ho et al. proposed that abrupt physical movements or vigorous activity may precipitate torsion in the absence of underlying pathology (9).

Despite the publication of recent pediatric case series, clinicopathological correlations and surgical decision-making in IFTT remain insufficiently characterized. The present study provides a detailed evaluation of the discrepancy between the degree of torsion and tubal viability, challenging the prevailing assumption that extensive torsion uniformly warrants salpingectomy. Furthermore, this study introduces the hypothesis that Müllerian (paramesonephric) and para-tubal cysts, frequently observed as leading etiologic factors in this cohort, may represent a continuum of the same pathological process in pediatric patients—a distinction with potential relevance for prophylactic surgical strategies. This study aims to address these knowledge gaps through a comprehensive clinicopathological review conducted at a major pediatric referral center. We present this article in accordance with the STROBE reporting checklist (available at https://tp.amegroups.com/article/view/10.21037/tp-2025-405/rc).

Methods

Electronic medical records were reviewed to identify cases coded with the International Classification of Diseases, 10th Revision (ICD-10) diagnosis code N83.503 (fallopian tube torsion) between January 1, 2020, and December 1, 2024. Simultaneously, records of patients who underwent surgical intervention for IFTT at Beijing Children’s Hospital, Capital Medical University, were screened for eligibility.

Inclusion criteria consisted of female patients under 18 years of age with intraoperative confirmation of IFTT, as documented in the operative report. Exclusion criteria included male patients, individuals aged 18 years or older, and cases with intraoperatively confirmed ovarian or other adnexal torsion.

Comprehensive chart reviews were performed to extract demographic and clinical data at the time of presentation. Collected variables included age, duration of abdominal pain, body mass index (BMI), associated symptoms (e.g., nausea and vomiting), imaging findings from ultrasonography (US) and computed tomography (CT), preoperative presumptive diagnosis, surgical approach, and histopathological results. Radiologic images were independently reviewed by a pediatric radiologist at Beijing Children’s Hospital, Capital Medical University, in conjunction with the corresponding dictated radiology reports.

The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Ethical Committee of Beijing Children’s Hospital, Capital Medical University (approval No. [2025]-E-083-R). Informed consent was secured from the parents or legal guardians of all included patients.

Statistical analysis

Data that follow a normal distribution are expressed as mean ± standard deviation, while data that do not follow a normal distribution are expressed as median along with the maximum and minimum values.

Results

Eighteen pediatric female patients were identified with the ICD-10 diagnosis code N83.503 during the study period. Patient ages ranged from 11 to 17 years, with a mean age of 12.19±1.58 years (Table 1). IFTT occurred with equal frequency on the left and right sides, each accounting for 50% (9/18) of cases.

The duration of abdominal pain prior to presentation was ≤24 hours in 50% (9/18) of patients, >24 to ≤72 hours in 22% (4/18), and >72 hours in 22% (4/18). One patient had undocumented duration data. Pain was typically localized to the lower abdomen and corresponded with the side of the affected fallopian tube. A history of chronic abdominal pain with acute exacerbation was present in 28% (5/18) of patients. Associated symptoms included non-projectile vomiting in 28% (5/18) and diarrhea in 6% (1/18) of patients. BMI ranged from 15.15 to 29.75 kg/m².

On physical examination, abdominal tenderness was identified in 72% (13/18) of patients, and rebound tenderness was observed in 11% (2/18). Abdominal US identified IFTT in 33% (6/18) of patients, demonstrating a twisted fallopian tube without ovarian involvement. In the remaining cases, IFTT was preoperatively misdiagnosed as ovarian torsion or an abdominal mass. Where US was inconclusive, non-contrast or contrast-enhanced CT was performed. However, CT imaging did not reliably differentiate IFTT from other causes of adnexal torsion, indicating limited diagnostic specificity in this context (Figure 1). Routine preoperative laboratory evaluations, including serum alpha-fetoprotein and human chorionic gonadotropin levels, were within normal limits in all patients.

Figure 1 Radiologic and intraoperative findings in IFTT. (A) CT image of IFTT. A round cystic lesion with a defined capsule is seen anterior to the rectum in the pelvic cavity, superior to the uterus. No significant enhancement is observed on contrast-enhanced imaging. Bilateral ovaries appear compressed and displaced. The fallopian tubes are not clearly visualized, and torsion or ischemia of the ovary cannot be confirmed. The red arrow indicates the cyst; blue arrows indicate the bilateral ovaries. (B) US image of IFTT. The red arrow indicates the vortex sign. The yellow arrow indicates the ovary with preserved blood flow. The pink arrow indicates the associated cyst. (C) Intraoperative findings of IFTT with an associated Müllerian cyst. The blue arrow indicates the twisted fallopian tube. The red arrow indicates the ischemic cyst. The green arrow indicates the ovary. CT, computed tomography; IFTT, isolated fallopian tube torsion; US, ultrasound.

All patients underwent laparoscopic surgical intervention at Beijing Children’s Hospital, Capital Medical University. Intraoperative findings confirmed IFTT in 100% (18/18) of cases. Hydrosalpinx was identified in 28% (5/18), while Müllerian or para-tubal cysts were observed in 72% (13/18). Salpingectomy was performed in 39% (7/18) of patients, while tubal preservation was achieved in 61% (11/18). No signs of ischemia or necrosis were noted in the ipsilateral ovaries (Table 2).

The degree of torsion ranged from 360 to 2,160°. In the case with the most extensive torsion (2,160°), detorsion restored blood flow and normal coloration of the fallopian tube and fimbriae, allowing preservation of the tube. In contrast, in some cases with lesser degrees of torsion (e.g., 540°), perfusion could not be restored, necessitating salpingectomy. Among patients who underwent salpingectomy, torsion ranged from 540 to 1,440°, whereas in those managed conservatively, torsion ranged from 360 to 2,160°. Hemoperitoneum was observed in 56% (10/18) of patients.

Postoperative histopathological examinations were performed in most cases. Müllerian cysts were confirmed in 44% (8/18), tubal hydrosalpinx in 28% (5/18), and para-tubal cysts in 28% (5/18) (Figure 2).

Figure 2 Histopathological features of a Müllerian cyst. (A) The child patient has a paramesonephric duct cyst beside the fallopian tube. The torsion section of the cyst forms double cystic cavities, lined with a single layer of cuboidal epithelium. The cyst wall consists of fibrous connective tissue, with mucus present within the cavity. Hemorrhage, necrosis are also visible in the cyst wall (HE, ×40). (B) Immunohistochemistry shows ER-positive cyst epithelial cells with stained nuclei (IHC, ×40). (C) Immunohistochemistry shows PR-positive cyst epithelial cells with stained nuclei (IHC, ×40). (D) Immunohistochemistry shows CK7-positive cyst epithelial cells with cytoplasmic staining (IHC, ×40). (E) Immunohistochemistry shows CD10-negative cyst epithelial cells (IHC, ×40). ER, estrogen receptor; HE, hematoxylin and eosin; IHC, immunohistochemistry; PR, progesterone receptor.

Discussion

IFTT represents a rare but important etiology of acute lower abdominal pain in females, particularly within pediatric and adolescent populations. This retrospective case series, comprising 18 surgically confirmed cases managed at Beijing Children’s Hospital, Capital Medical University, provides clinically relevant data on presentation patterns, diagnostic limitations, intraoperative findings, and surgical outcomes associated with this uncommon condition.

Clinical presentation and diagnostic challenges

The mean age of patients in this study was 12.19 years, consistent with previous literature suggesting that IFTT most frequently occurs in perimenarchal or adolescent females (4,6). All patients presented with unilateral lower abdominal pain localized to the side of torsion, emphasizing the potential diagnostic relevance of laterality. However, this clinical feature alone is rarely sufficient to distinguish IFTT from more common causes of acute abdominal pain, such as appendicitis or ovarian torsion (10).

Despite the relatively consistent symptomatology, preoperative diagnosis of IFTT remains challenging. In this case series, US correctly identified IFTT in only 33% (6/18) of patients, with the remaining cases misdiagnosed as ovarian torsion or non-specific abdominal masses. These findings align with prior studies that have reported similarly low sensitivity and specificity of sonographic evaluation for IFTT in pediatric populations (5,11,12). While sonographic features, such as a dilated, twisted tubular structure in the presence of normal-appearing ovaries, may raise suspicion for IFTT, these findings are frequently subtle and easily overlooked (13).

CT was utilized when US findings were inconclusive; however, CT imaging also failed to provide definitive diagnoses in most cases. Although CT may demonstrate adnexal masses or fallopian tube enlargement, such findings lack specificity and may overlap with other gynecologic or gastrointestinal pathologies. These limitations reinforce the restricted diagnostic utility of CT in the evaluation of IFTT and underscore the importance of maintaining a high index of clinical suspicion. In suspected cases, early surgical exploration remains essential to prevent irreversible tubal damage and optimize fertility-preserving outcomes.

Surgical management and intraoperative findings

All patients in this case series underwent laparoscopic surgery, which remains the standard approach for both diagnostic confirmation and therapeutic intervention in cases of adnexal torsion, including IFTT (14). Intraoperative findings confirmed IFTT in all cases. The degree of torsion varied widely, ranging from 360 to 2,160°, with no consistent correlation between the number of twists and the extent of ischemia or necrosis. This observation is consistent with prior reports indicating that the severity of torsion does not reliably predict tubal viability (15-17).

Notably, in the patient with the highest degree of torsion (2,160°), detorsion successfully restored tubal perfusion. Conversely, in another case with a lesser degree of torsion (540°), perfusion could not be re-established, necessitating ipsilateral salpingectomy. These findings highlight the critical role of intraoperative assessment, particularly the evaluation of tubal color, turgor, and bleeding response following detorsion, rather than relying solely on the degree of torsion as a determinant of tissue viability.

Among patients who required salpingectomy, the degree of torsion ranged from 540 to 1,440°. In contrast, in those for whom tubal preservation was achieved, torsion ranged from 360 to 2,160°. These findings further underscore the need for individualized surgical decision-making guided by direct intraoperative visualization, rather than preoperative imaging or theoretical estimates of torsion severity. This analysis provides a significant insight from our case series, challenging the assumption that a higher degree of torsion necessarily indicates irreversible ischemic injury. An attempt at detorsion with the goal of preserving reproductive potential should be considered in all pediatric patients, regardless of torsion extent.

While the role of hydrosalpinx in the recurrence of torsion remains insufficiently understood, there is currently limited evidence regarding the long-term risk of recurrence following detorsion in pediatric patients. Therefore, preservation of fallopian tube tissue should be prioritized whenever feasible during adolescence. Postoperative surveillance with pelvic US is advisable to monitor for recurrence, particularly in cases with residual or recurrent hydrosalpinx, which may predispose to re-torsion.

Etiologic factors and histopathological findings

Histopathological examination identified underlying structural abnormalities in the majority of cases. Müllerian cysts were observed in 44% (8/18), para-tubal cysts in 28% (5/18), and hydrosalpinx—secondary to tubal atresia—in 28% (5/18). These findings are consistent with previous studies suggesting that para-tubal cysts and congenital anomalies, such as hydrosalpinx or excessive tubal length, may predispose pediatric patients to IFTT (18).

The frequent coexistence of IFTT with Müllerian or para-tubal cysts supports a potential mechanical etiology, whereby mass effect or increased tubal mobility may contribute to torsion. These observations align with the prevailing hypothesis that both intrinsic factors (e.g., congenital elongation or structural anomalies) and extrinsic factors (e.g., cysts or pelvic masses) play contributory roles in the pathogenesis of IFTT (13). In pediatric patients, hormonal fluctuations associated with puberty may further affect tubal motility and increase the risk of torsion.

In this series, the frequent association of IFTT with Müllerian or para-tubal cysts supports the hypothesis that these two cyst types may represent a histopathological continuum in the pediatric population. This proposed unifying pathological spectrum constitutes a novel conceptual contribution of the present study and may inform future investigations into the developmental origin and management of these lesions. At Beijing Children’s Hospital, such cysts are frequently detected incidentally during routine physical examinations. The potential role of prophylactic surgical intervention in preventing IFTT among these patients represents an important direction for further research.

In all cases included in this series, IFTT was associated with identifiable pathological findings, most commonly cysts or hydrosalpinx, suggesting that structural abnormalities constitute a primary etiological factor in this population. The underlying pathogenesis of IFTT may parallel that of torsion of the epididymal appendage, with both conditions believed to originate from remnants of the mesonephric duct. These findings underscore the importance of recognizing congenital or acquired structural anomalies as key contributors to adnexal torsion in pediatric patients.

Laparoscopic exploration should be performed promptly when imaging confirms or strongly suggests torsion. In cases where ultrasound identifies hydrosalpinx or para-ovarian cysts without definitive evidence of IFTT, close clinical monitoring is warranted. If abdominal pain persists without improvement, surgical exploration should be considered. Timely diagnosis remains critical for optimizing clinical outcomes. US demonstrates relatively high sensitivity in identifying adnexal torsion in the presence of structural abnormalities. The detection of an adnexal lesion with torsion on US constitutes a clear surgical indication. Furthermore, identification of a cyst in patients with suspected IFTT may support early operative management to prevent irreversible ischemic injury and preserve reproductive function.

These findings reinforce the need for increased clinical awareness of IFTT among pediatric surgeons and gynecologists. Enhanced familiarity with its atypical presentation and structural associations may facilitate early diagnosis, timely intervention, and fertility-preserving outcomes in affected patients.

Limitations

This study has several limitations. Most notably, long-term follow-up data on tubal function and fertility outcomes were not available, which limits the ability to evaluate the true impact of conservative versus radical surgical management. As this was a retrospective study, post-discharge follow-up posed logistical challenges. Additionally, all patients included in this series have since transitioned to adult care, making it currently unfeasible to assess long-term gynecological or reproductive outcomes. Efforts to obtain follow-up data are ongoing and will be incorporated into future investigations aimed at better understanding the hormonal and developmental factors associated with IFTT.

Furthermore, due to the rarity of IFTT in clinical practice, no control group was included. This precluded comparative analysis with other adnexal pathologies. However, intraoperative observations from this study suggest that IFTT differs from isolated ovarian torsion at the pathophysiological level—an area that warrants further investigation.

Conclusions

This study underscores the diagnostic and therapeutic challenges associated with IFTT in pediatric patients. IFTT is frequently associated with structural anomalies, including remnants of the mesonephric duct, Müllerian or para-tubal cysts, and hydrosalpinx. Clinical symptoms are typically non-specific, and imaging findings are often inconclusive. However, US demonstrates relatively high sensitivity, as most cases exhibit cystic adnexal structures or signs of hydrosalpinx.

Given the limitations of imaging in definitively diagnosing IFTT, early laparoscopic intervention remains the most reliable approach for both confirmation and treatment. Intraoperative findings should guide surgical decision-making: detorsion is recommended when tubal viability is preserved, while salpingectomy is appropriate in cases of irreversible ischemic injury or confirmed cystic pathology to reduce recurrence risk.

Based on intraoperative and histopathological observations, it is hypothesized that Müllerian and para-tubal cysts may represent a single pathological spectrum in the pediatric population. This warrants further investigation. In several patients, hydrosalpinx was also noted intraoperatively. However, tissue sampling was not feasible in all cases due to the use of windowing techniques during laparoscopy.

This case series offers two principal contributions. First, it provides intraoperative evidence that the degree of torsion should not be used as the sole criterion for salpingectomy, supporting a more conservative, fertility-preserving approach where feasible. Second, it proposes a unifying hypothesis for the cystic lesions associated with pediatric IFTT, offering a new framework for understanding its etiology.

These insights contribute to refining the clinical management of this rare condition and underscore the need for heightened awareness among pediatric surgeons and gynecologists. Future multicenter studies are warranted to evaluate the long-term outcomes and optimize surgical decision-making in conservatively managed IFTT.

Acknowledgments

We would like to acknowledge the hard and dedicated work of all the staff that implemented the intervention and evaluation components of the study.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://tp.amegroups.com/article/view/10.21037/tp-2025-405/rc

Data Sharing Statement: Available at https://tp.amegroups.com/article/view/10.21037/tp-2025-405/dss

Peer Review File: Available at https://tp.amegroups.com/article/view/10.21037/tp-2025-405/prf

Funding: This study was supported by the Changzhi Basic Research Project (No. JC202436). The funding body had no role in the design of the study and collection, analysis, and interpretation of data and in writing the manuscript.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tp.amegroups.com/article/view/10.21037/tp-2025-405/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Ethical Committee of Beijing Children’s Hospital, Capital Medical University (approval No. [2025]-E-083-R). Informed consent was secured from the parents or legal guardians of all included patients.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Hagege R, Sharvit M, Hamou B, et al. Isolated Fallopian Tube Torsion: An Underdiagnosed Entity with Debatable Management. J Minim Invasive Gynecol 2022;29:158-63. [Crossref] [PubMed]
2. Schwartz B, Weerasooriya N, Mercier R, et al. Factors Associated With Isolated Fallopian Tube Torsion in Pediatric Patients. J Pediatr Surg 2024;59:1538-44. [Crossref] [PubMed]
3. Meyer R, Meller N, Mohr-Sasson A, et al. Clinical features of isolated Fallopian tube torsion: evidence from a large series. Hum Fertil (Camb) 2023;26:971-7. [Crossref] [PubMed]
4. Crosier CJ, Ricca RL. Isolated Fallopian Torsion: A Pediatric Case Series. Am Surg 2023;89:3917-9. [Crossref] [PubMed]
5. Bertozzi M, Noviello C, Molinaro F, et al. Isolated fallopian tube torsion in pediatric age: An Italian multicenter retrospective study. J Pediatr Surg 2020;55:711-4. [Crossref] [PubMed]
6. Boukaidi SA, Delotte J, Steyaert H, et al. Thirteen cases of isolated tubal torsions associated with hydrosalpinx in children and adolescents, proposal for conservative management: retrospective review and literature survey. J Pediatr Surg 2011;46:1425-31. [Crossref] [PubMed]
7. Gaied F, Emil S, Lo A, et al. Laparoscopic treatment of isolated salpingeal torsion in children: case series and a 20-year review of the literature. J Laparoendosc Adv Surg Tech A 2012;22:941-7. [Crossref] [PubMed]
8. Arredondo Montero J, Guillén Redondo P, Bronte Anaut M. Snapshots Quiz. Br J Surg 2021;109:29. [Crossref] [PubMed]
9. Ho PL, Liang SJ, Su HW, et al. Isolated torsion of the fallopian tube: a rare diagnosis in an adolescent without sexual experience. Taiwan J Obstet Gynecol 2008;47:235-7. [Crossref] [PubMed]
10. Verpalen IM, de Boer J, van den Hoed RD, et al. Isolated fallopian tubal torsion; rare or overlooked?. Ned Tijdschr Geneeskd 2018;162:D2670.
11. Mariani A, Hameury F, Dubois R, et al. Isolated Fallopian Tube Torsion in Children With Hydrosalpinx: Is Conservative Management an Option?. Pediatr Emerg Care 2024;40:582-5. [Crossref] [PubMed]
12. Varghese S, Seldon Y, Raperport C, et al. Isolated fallopian tube torsion: A systematic review of case reports. Eur J Obstet Gynecol Reprod Biol 2024;296:140-7. [Crossref] [PubMed]
13. Tamir Yaniv R, Ravid E, Halevy N, et al. The Sonographic Characteristics of Isolated Fallopian Tube Torsion. J Minim Invasive Gynecol 2025;32:270-8. [Crossref] [PubMed]
14. Yazawa R, Yazawa H, Anjyo K, et al. Four cases of isolated fallopian tube torsion successfully treated with laparoscopic surgery:A case series. Fukushima J Med Sci 2024;70:163-8. [Crossref] [PubMed]
15. Qian L, Wang X, Li D, et al. Isolated fallopian tube torsion with paraovarian cysts: a case report and literature review. BMC Womens Health 2021;21:345. [Crossref] [PubMed]
16. Somers B, Murugandoss N. Isolated fallopian tube torsion due to a large paratubal cyst in an adolescent patient. BMJ Case Rep 2025;18:e266101. [Crossref] [PubMed]
17. Pan S, Murong Z, Zhu Y, et al. Discussion on relationship between meridians and viscera of decreased ovarian reserve from the perspective of “preventive treatment of disease” by acupuncture. World J Tradit Chin Med 2023;9:111-22.
18. Demirel BD, Hancioglu S, Bicakci U, et al. Isolated tubal torsion: A rare cause of acute abdomen in childhood. Pediatr Rep 2018;10:7604. [Crossref] [PubMed]