A rare cause of pediatric acute abdominal pain: isolated Fallopian tube torsion

A 14-year-old girl presented at our hospital with severe lower quadrant pain, which had been ongoing for 6 hours, and nausea and vomiting. Physical examination revealed diffuse tenderness, rebound, and defence on all lower quadrants, mainly in the left lower quadrant. The laboratory test results were unremarkable.

Sonographic examination revealed a midline, tubular cystic mass lying deep below the uterus. The mass had a beaked, tapering appearance, directed towards the left adnexa. (Figure 1).   The uterus was sonographically normal, and stromal vascularization was present in both ovaries. A 2 cm diameter, simple follicle cyst was observed in the right ovary. A small amount of simple free fluid was present within the pelvis (Figure 2). Patient underwent laparotomy for suspected fallopian tube torsion.

Background: Isolated tube torsion (ITT) is defined as isolated torsion of the Fallopian tube in the absence of ovarian torsion. Its prevalence ranges between 1:500.000 and 1:1.500.000 [1].

The pathogenesis of ITT has been explained as mechanical obstruction of adnexal veins and lymphatics, leading to pelvic congestion and edema with subsequent enlargement of the fimbria, thereby resulting in  partial or complete torsion of the involved tube [2].There is also a higher probability of right-side tubal torsion than left due to the position of the sigmoid colon and slow venous drainage of the right tube [3]. ITT usually occurs spontaneously, but may also occur secondary to an underlying adnexal pathology such as an abnormally long tube/mesosalpinx, premenarchal hormonal activity leading to adnexal congestion and increased tubal motility, or paraovarian/paratubal cysts [4].

Clinical perspective: Patients usually present with sudden onset of lower quadrant pain that can be sharp and radiating to the thigh or groin. The most common symptoms in pediatric case series are abdominal pain, vomiting and fever, respectively [5].

Complications from tubal torsion include fallopian tube necrosis and the development of gangrene. The progression of local necrosis may cause irreversible damage to the ipsilateral ovary [6].

A delay in diagnosis can lead to loss of fertility as it causes irreversible tubal damage. Therefore, early diagnosis and treatment is essential [5].

Imaging perspective: Pelvic free fluid and an enlarged tube with thickened echogenic walls are the basic sonographic findings. A curved echogenic mass indicating internal debris or a thickened/ twisted tube may also be seen. Computed Tomography (CT) and Magnetic resonance imagining (MRI) can reveal an adnexal mass, a twisted fallopian tube, and a dilated tube larger than 15 mm with a thickened wall. Free intrapelvic fluid, peritubular fat stranding, a thick, enhanced broad ligament, and regional ileus are some of the secondary signs. MRI may show the “whirlpool” sign, an indicator of physical torsion of tubes [7,8]. Uterus and ovaries may be normal.

Outcome: More than 10 hours between the onset of pain and surgical exploration increases the risk of tubal necrosis [1]. Treatment options for isolated tube torsion include detorsion or salpingectomy, depending on the timing of the surgical intervention and the presence of complications. Laparoscopy is recommended as the primary approach [9].

Take home message: Isolated tubal torsion is a rare cause of pelvic pain. In a case with a tubular, beak-shaped, cystic pelvic mass and with no significant laboratory abnormalities, isolated tubal torsion should be kept in mind.

Consent for the use of medical data and US images was obtained both from the patient and the parents.