Introduction
Isolated torsion of the fallopian tube without an ovarian abnormality is an uncommon event, with an incidence of approximately 1 in 1,500,000 females [
1]. Risk factors for isolated torsion of the fallopian tube include prior tubal ligation, hydrosalpinx, pelvic inflammatory disease (PID), a long or congested mesosalpinx, (para)tubal tumors, Morgagni hydatids, and trauma. Presenting symptoms of isolated torsion of the fallopian tube include acute onset of lower abdominal pain that may be accompanied by nausea, vomiting, and peritoneal signs. Since the first description of isolated torsion of the fallopian tube by Bland Sutton in 1890 [
2], a number of patients have been reported and generally presented during the reproductive age. Isolated torsion of the fallopian tube rarely occurs in pre-pubertal girls [
3,
4]. Isolated torsion of the fallopian tube is also extremely rare during the post-menopausal period because of hypotrophy of the fallopian tube and the blood supply [
5]. The purpose of this report was to describe the clinical presentation, objective findings, and surgical outcomes of two cases of isolated fallopian tube torsion that arose in patients at age extremes.
Discussion
Fallopian tube torsion is an uncommon gynecologic cause of acute lower abdominal pain in females [
6]. Although the causative mechanism underlying isolated torsion is not fully understood, many predisposing factors that could possibly lead to this condition have been suggested; these factors are divided into intrinsic and extrinsic causes [
7,
8]. Intrinsic causes, which are directly related to the fallopian tube, include congenital anomalies, hydrosalpinx, hematosalpinx, tubal ligation, tubal neoplasms, hypermobility, spasm, and autonomic dysfunction of the fallopian tube [
3,
7‐
9]. Extrinsic causes, which are attributable to changes in organs proximal to the fallopian tube, include ovarian or paratubal masses, uterine enlargement by pregnancy or tumors, adhesions, mechanical factors, and trauma to the pelvic organs [
3,
7‐
9].
In our patients, the most probable causes of isolated fallopian tubal torsion were a tubal tumor (case 1) and a hydrosalpinx (case 2). A tubal tumor that is pedunculated and located near the fimbria is referred to as a hydatid cyst of Morgagni; however, Morgagni hydatids are usually <2 cm in size [
10], and was thus unlikely the etiology of the torsion in case 1. Based on the macroscopic findings, we believe that there was the possibility of an adenofibroma of the fallopian tube, although it was impossible to confirm on histology.
The main causes of hydrosalpinx in women include PID, previous abdominal surgery, endometriosis, and ectopic pregnancies; however, the causes differ in sexually inactive girls. In case 2, our patient had not had her sexual debut and had no history of PID, appendicitis, or peritonitis. In addition, the histologic examination revealed no obvious signs of inflammation or mass lesions in the resected fallopian tube. A possible explanation for the hydrosalpinx was a congenital malformation of the fallopian tube or a previous asymptomatic episode of PID, which caused distal occlusion of her fallopian tube.
The correct pre-operative diagnosis of an isolated tubal torsion is very difficult because the symptoms are non-specific and common to many other conditions. Even when imaging studies identify a pelvic mass, no specific clinical feature is pathognomonic for a torsion involving the entire adnexa. USG is often the first imaging modality in a female with acute abdominal and/or pelvic pain because a USG is non-invasive and there is no radiation exposure. Typically, USG findings in patients with torsion of the fallopian tube include a dilated tube with thickened echogenic walls and tapered ends, internal free fluid with debris, and surrounding inflammation [
11]; however, these findings are not definitive in establishing a diagnosis of fallopian tube torsion. A CT scan is especially useful for excluding appendicitis in patients with right lower abdominal pain in the acute setting. In addition, multiplanar reformatted images of CT scans can be helpful in visualizing typical findings, such as a dilated fluid-filled structure, tapered ends, and configuration of the mass in fallopian tube torsion [
12]. Although MRI may not be routinely used in the emergency setting, the superior soft tissue contrast and multiplanar capability make it possible to distinguish a normal ovary from a cystic mass [
11]. During the diagnostic process in case 2, digital and vaginal examinations and a vaginal USG were not performed because of our patient’s age; the diagnostic imaging by CT and MRI were therefore critical to establish a pre-operative diagnosis. In fact, we were able to correctly establish a pre-operative diagnosis of isolated fallopian tube torsion owing to the clinical presentation combined with the diagnostic imaging.
Treatment by laparoscopy is recommended for patients with adnexal torsion because of a smaller wound, less blood loss, and a shorter hospital stay [
13]. Even for a pregnant patient, the laparoscopic approach is useful and more feasible during the first and second trimesters [
14]. Unfortunately, salvage of the fallopian tube is rare because of the difficulty in making a correct pre-operative diagnosis. Removal of the fallopian tube is generally recommended when the fallopian tube cannot be salvaged. Immediate release of torsion is always recommended, especially for reproductive-aged women because it is not clear when irreversible damage takes place in the twisted fallopian tube. As one of the oviduct-sparing options in children and adolescents with hydrosalpinx, Boukaidi
et al. [
15] proposed a two-step conservative surgical management. The first step includes the treatment of acute episodes of torsion by laparoscopic detorsion, puncture, and evacuation of the affected fallopian tube. The second step includes second-look laparoscopic and salpingoscopic surgery scheduled several weeks after the first surgical procedure [
15]. Considering adnexal torsion involving the ovary in a pediatric patient in whom detorsion and ovarian salvage is thought to be a safe option, even when the ovary appears necrotic, this oviduct-sparing option could be adapted to isolated fallopian tubal torsion.
Conclusions
We present two very rare cases of isolated fallopian tubal torsion. Radiologic interventions, such as CT, MRI, and USG, were helpful diagnostic tools in recognizing this medical emergency. Isolated torsion of the fallopian tube should be considered in the differential diagnosis of lower abdominal pain with a cystic mass and a normal ipsilateral ovary in all female patients, regardless of age. Prompt surgical intervention is required to prevent progression to peritonitis and maximize the likelihood of salvaging the fallopian tube.
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
MT analyzed and interpreted the patient data, drafted the manuscript, and created the figures. HM, KK, YY, TK, SI, HM, TS, RM, NI, KA, YT, and HI performed the physical examinations and provided the medical care. KS supervised case 1 and YK supervised case 2. All authors read and approved the final manuscript.