Isolated fallopian tube torsion is defined as rotation of the fallopian tube around its longitudinal axis with preserved normal ovary. Isolated fallopian tube torsion is a rare cause of acute pelvic pain in female patients, with estimated incidence of about one in 1.5 million females.

Abstract: Isolated fallopian tube torsion is defined as rotation of the fallopian tube around its longitudinal axis with preserved normal ovary. Isolated fallopian tube torsion is a rare cause of acute pelvic pain in female patients, with estimated incidence of about one in 1.5 million females. Ultrasound examination is the first choice of imaging modality. The specific sign of tubal torsion in ultrasound is the ‘whirlpool’ sign due to twisted vascular pedicle. In a case of acute pelvic pain with normal ovaries, a whirlpool mass due to twisted vascular pedicle adjacent to the normal appearing ovary is more specific for diagnosis of isolated fallopian tube torsion. The management of choice is the laparoscopic examination with conservative approach: detorsion of fallopian tube with para-ovarian cyst removal.

Keywords: Isolated fallopian tube torsion, Ultrasound, Laparoscopy

Authors: Fatemeh Shakki Katouli1,2, Fahimeh Azizinik1,3, Leila Bayani1,2, Ameneh Abiri4, Behnaz Ghavami5 

1. Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Tehran University of Medical Sciences, Tehran, Iran

2. Department of Radiology, Arash Women Hospital, Tehran University of Medical Sciences, Tehran, Iran

3. Department of Radiology, Amiralam and Yas Hospitals, Tehran University of Medical Sciences, Tehran, Iran

4. Department of Obstetric and Gynecology, Arash Women Hospital, Tehran University of Medical Sciences

5. Department of Gynecology Laparoscopic Surgery, Arash Women Hospital, Tehran University of Medical Sciences

Reviewers: Karen Fung-Kee-Fung

View the Patient Information sheet


Isolated fallopian tube torsion (IFTT) refers to an isolated tubal torsion, while the ipsilateral ovary and its blood and lymphatic flow remain unaffected. For the first time, this entity was described by Bland-Sutton in 1890 (1).

Three types of IFTT are described:

Type 1: IFTT torsion along its long axis

Type 2: IFTT torsion along its long axis with an associated dilated fimbriated end and a lead mass

Type 3: IFTT torsion along its short axis (2)

IFTT is a rare cause of acute pelvic pain in female patients. The diagnosis of IFTT may be challenging when presented with intact ovarian appearance on the ultrasound examination. There is often significant delay in diagnosis because of the rarity of occurrence of IFTT (3).

Patients usually present with acute pelvic or lower abdominal pain, nausea/vomiting, peritoneal signs, and sometimes with palpable adnexal mass. Various types of abdominal pain may occur including: acute or subacute, intermittent or persistent, severe or mild, sometimes with radiating pain to the groins or thighs (3,4).

Adnexal or cervical motion tenderness usually occurs on bimanual examination in adults, but it cannot be applicable in pediatric patients. Laboratory markers like WBC or CRP may be elevated. Leukocytosis was observed in 29.4-63% of the patients (5,6).

Duration of clinical symptoms lasting more than three days is defined as chronic torsion (7).


IFTT dominantly affects women of reproductive age. It is relatively uncommon in pediatric patients and rarely seen in postmenopausal women. This entity is estimated to have an incidence of about one in 1.5 million females (3).

Right-sided predilection has been reported in the literature, likely due to an increased surgical exploration of the right adnexa during investigation of possible appendicitis in patients with acute right lower quadrant abdominal pain. Other theories presume a right-sided preponderance due to the protective effects of the sigmoid colon on the left fallopian tube (3,8).


Several predisposing factors have been suggested for fallopian tubal torsion. 

These factors can be classified in two main categories (3,9-15):

  1. Primary (intrinsic causes): including anatomic malformations in the mesosalpinx or tube ( such as elongated mesosalpinx, spiral course of the salpinx or hydatid cysts of Morgagni i.e. thin-walled smooth pedunculated cysts arising from the fallopian tube), tubal ligation, any process that enlarges the tube such as a hydrosalpinx or tubal neoplasm, and abnormal peristalsis of the tube caused by autonomic dysfunction or the effects of certain drugs
  2. Secondary (extrinsic causes): including pelvic adhesions, pelvic inflammatory disease, adnexal venous congestion leading to spiraling of veins and resultant engorgement of the fimbria end of the fallopian tube, adjacent ovarian or para-ovarian masses, uterine masses, post-partum or gravid uterus, and sudden changes in body position and trauma.


Some factors have been proposed for fallopian tube torsion in pediatric patients such as abnormal length of the mesosalpinx or a spiral course of the salpinx, and pre-menarche hormonal changes leading to activation of ovarian and tubal function (16).

Isolated tubal torsion can also occur in pregnancy or in cases of mullerian uterine anomaly (17,18).


Transabdominal or transvaginal ultrasound is the first choice of imaging modality because of its availability, cost-effectiveness and lack of ionizing radiation. The gold standard for establishing the diagnosis and treatment is laparoscopy, the minimally invasive surgery with fast recovery. Laparoscopy is also recommended for women in the first or second trimester of pregnancy.


Ultrasound Findings:

Normal uterus and bilateral ovaries with preserved arterial blood flow should be detected in isolated fallopian tube torsion.

The typical finding is that of a serpiginous tubular structure or elongated, convoluted cystic mass, sometimes with more complex or solid-appearing components, as well as with thickened echogenic walls and internal debris (19). The structure should be located between the ovary and uterus and tapered as it nears the uterine cornua. The fallopian tube walls are usually edematous with prominent endosalpingeal folds (3).

Features that have been shown to indicate a tubal origin in a cystic adnexal mass include a tubular shape, a folded configuration, incomplete septa, and opposed indentations in the wall of the mass (cogwheel appearance)(20). Convoluted echogenic mass maybe seen due to thickened and twisted tube (21). A “beaked” appearance adjacent to the cystic structure has also been described.

A part of enlarged twisted fallopian tube could mimic a cystic adnexal mass. In these cases, the beaked appearance of this structure may be a clue for diagnosis of tubal torsion. The apex of beaked appearance is toward the site of the torsion (3). 

The most specific sign of tubal torsion in ultrasound is the ’whirlpool’ sign due to twisted vascular pedicle (22). In a case of acute pelvic pain with normal ovaries, a whirlpool mass due to twisted vascular pedicle adjacent to the ovary is the most specific sign for diagnosis of isolated fallopian tube torsion, but sensitivity depend on operator experience.

High resistance, reversal or absence of vascular flow in the tube wall has also been reported (24). However, presence of normal flow does not exclude the diagnosis due to dual vascular supply of both tube and ovary. The fallopian tubes and ovaries receive their vascular supply from both ovarian and uterine arteries. So, it is possible for the fallopian tube to undergo torsion without compromising the arterial blood flow of the ipsilateral ovary (3).The uterus usually shifts to the twisted side dependent on lesion size (23).


CT scan findings:

In isolated fallopian tube torsion a twisted serpiginous adnexal mass may be seen as tubular or comma-shaped structure extending from the uterine cornua.

The dilated tube often shows thickened walls with enhancement. Hyperdensity of internal content could be seen in cases of hemorrhage inside the tube in pre-contrast CT images.

The indirect signs include pelvic free fluid, peritubal fat stranding, ileus in adjacent bowel loops, broad ligament stranding and thickening (21,25). The “bird's beak” sign at the site of hydropic tubal torsion, similar to closed loop bowel obstructions or volvulus, could be helpful for diagnosis of this entity (3). An adnexal mass, sometimes with hemorrhage in the mass, has also reported (21).

Skinner et al. suggested that the thickened broad ligament as streaky soft tissue density adjacent to hypodense mass with “rat tail” appearance is highly suggestive of an acute inflammatory process such as tubal torsion and “rat tail” sign may be useful to distinguish between torsion and pelvic tumors (26).

Meng Liao et al. described a chronic tubal torsion as a twisted dilated fallopian tube with thickened and calcified walls, forming a large lesion that can be mistaken with a cystic-solid tumor. The remained twisted fallopian tube showed high density, suggesting hemorrhagic changes.

The punctate or short strips of calcification inside the fallopian tube wall have been reported in chronic tubal torsion (27).


MRI Finding:

Magnetic resonance imaging (MRI) has been described only in a few cases in the literature. It can be particularly illuminating  in the pregnant patient with equivocal ultrasound findings or in conditions which TVS is impossible, such as a  virginal patient or in the setting of significant vaginismus.

The normal appearance of the ovary on the affected side with prominent plicae tubariae of the twisted fallopian tube, and the whirlpool or beak signs are the most common recognized MRI findings (28).

A longitudinal fluid-filled structure with incomplete folds or T2-hypointense mural nodules represents a fallopian tube lesion (29,30).

Bloody tubal content has been suggested as a specific finding for fallopian tube torsion (31). High signal intensity in T1WI without contrast enhancement of the fallopian tube wall could be suggestive for hemorrhagic necrosis. Also high signal on DWI may be detected in tube wall (28).

The coiling sign of the dilated fallopian tube is also described in both CT and MRI (18).

Fallopian tube preservation is much more likely when the intervention can be done within 24 hours of patient clinical presentation (31). So, correct and prompt diagnosis is crucial to decrease the complication rate  and preserve fertility in women of reproductive age.

Differential Diagnosis

Isolated tubal torsion is uncommon; however, it is important to be considered in the differential diagnosis of acute lower abdominal pain because a delay in intervention may fail to save the tube (32).

Differential diagnoses mainly include the other causes of lower abdominal pain in women of reproductive age: tube-ovarian torsion, ectopic pregnancy, endometriosis, pelvic inflammatory disease, ruptured ovarian cyst, degenerative leiomyoma, acute appendicitis, and other gastrointestinal and urinary conditions.

Moreover, in pregnant women, the obstetric causes of lower abdominal pain should be included in differential diagnoses like abruptio placentae and uterine rupture. In addition, symptoms may be masked by a concomitant or consequent term or preterm labor (33).

Tubo-ovarian torsion is the main differential diagnosis. The fallopian tube was the only twisted organ in 9.3% of patients with surgical diagnosis of adnexal torsion (34). In ovarian torsion, the stromal edema manifests with ovarian enlargement, hypoechoic heterogeneous central medulla, peripheral small follicles (string of pearls), and follicular ring sign (35).

It is critical to diagnosis and treat IFTT early in the course of the disease, especially within the first 24 hours. The progression of torsion can lead to hematosalpinx, tubal rupture and peritubal hematoma, which can easily be misdiagnosed as ectopic pregnancy on ultrasound examination (36).

Considering the risk of necrosis and superinfection, the imaging and clinical presentation can easily mimic the pelvic inflammatory disease.


The management of choice is the laparoscopic detorsion of fallopian tube with para-ovarian cyst removal. Salpingectomy is preferred when there is any suspicion of irreversible ischemic damage (no color change after detorsion) or presence of significant adhesion (37).

It should be considered that in the following situations, unilateral salpingo-oophorectomy is the preferred approach;

1- in patients with any suspicion of malignant underlying cause

2- concurrent ovarian cyst

3- patients over 45 years old without planning for future pregnancy (38)

Moreover, in patients with fertility problems and hydrosalpinx who develop IFTT, the preferred approach is salpingectomy.


There is no reference concerning the golden time from onset of symptoms to treatment in order to preserve tubal viability. Tubal viability is related to many factors, including the degree of ischemia, tightness of the  torsion, and the underlying condition of the fallopian tube  rendering it prone it to torsion (38).

Mechanical obstruction caused by tubal torsion can impair the vascularity and lead to tubal congestion and edema. Longstanding torsion can cause tubal infarction, hemorrhagic necrosis and gangrene with increased risk of hemoperitoneum and peritonitis, and may result in salpingectomy of the affected side (32). In addition, local necrosis can cause significant damage to the normal adjacent ovary.

Although the conservative management approach suggests detorsion without salpingectomy to preserve fertility in women of reproductive age, there may be an increased risk of recurrent torsion in a few cases (39).

Salpingectomy, due to adnexal non-viability or presence of underlying hydrosalpinx, alters the chance of future fertility (21).


In summary, IFTT is a rare cause of acute lower abdominal pain with prevalence in women of reproductive age. Ultrasound is the first imaging modality for evaluating female pelvis in acute conditions. In ultrasound, a twisted pedicle with a normal appearing ovary, sometimes with an adnexal cyst, is the dominant diagnostic feature. 

The “whirlpool” sign is the most specific finding for accurate diagnosis in sonography with sensitivity based on operator experience. Early diagnosis is so critical to preserve tubal viability and future fertility, as it occurs dominantly in reproductive age. Early diagnosis and treatment are essential to prevent irreversible ischemic changes and further complications.


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This article should be cited as: Katouli F, Azizinik F, Bayani L, Abiri A, Ghavami B: Isolated Fallopian tube Torsion, Visual Encyclopedia of Ultrasound in Obstetrics and Gynecology,, October 2023.

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