Fallopian tube torsion

A Fallopian tube torsion is a type of adnexal torsion and usually occurs in association with an ovarian torsion (when it is then termed a tubo-ovarian torsion). An isolated fallopian tube torsion is rare but can occur. 

Pathology

An isolated tubal torsion can occur as a late complication of tubal ligation ^1,2.

Other risk factors for an isolated fallopian tube torsion include ^3,8 

• intrinsic factors
  • pelvic inflammatory disease (PID)
  • anatomical abnormalities
    • hydrosalpinx
    • hematosalpinx: can also be a consequence
    • long mesosalpinx 
  • physiological abnormalities
    • tubal spasm
    • hypermotility of tube
  • tubal neoplasm
• extrinsic factors 
  • adhesions
  • adnexal venous congestion
  • adjacent ovarian or paraovarian masses (e.g. paraovarian cysts)
  • uterine masses
  • gravid uterus

Location

There is a well-recognized right-sided predilection ⁹

Radiographic features

Ultrasound

Reported sonographic findings include ^3,5

• a normal-appearing uterus and ovaries with normal flow
• free fluid
• a dilated tube with thickened, echogenic walls and internal debris 
• a convoluted echogenic mass thought to represent a thickened, torsed tube
• sonographic whirlpool sign: described as a relatively specific sign of tubal torsion ⁷

CT

Reported primary CT findings of isolated tubal torsion include ^3,4

• an adnexal mass
• twisted appearance to the fallopian tube with dilated tube greater than 15 mm
• thickened and enhancing tubal wall and luminal CT attenuation greater than 50 HU, compatible with hemorrhage

Secondary signs include

• free intrapelvic fluid
• peritubular fat stranding
• enhancement and thickening of the broad ligament
• regional ileus