Paraovarian cysts

Female
teenager with left lower quadrant pain. Coronal (left) and axial (above left) CT with contrast of the abdomen shows a large, simple, fluid-filled structure above the bladder which is arising from the left ovary. Axial CT (below right) obtained more inferiorly shows a second, smaller, fluid-filled structure in the midline between the uterus and rectum which is in close association with the right ovary which is just to the right of the uterus.The diagnosis was a large left ovarian cyst and a right paraovarian cyst.
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Paraovarian cysts are remnants of Wolffian duct in the mesosalpinx that do not arise from the ovary. They account for ~10-20% of adnexal masses .

Terminology

Paraovarian cysts are also sometimes referred to as paratubal cysts or hydatid cysts of Morgagni .

Epidemiology

They typically occur in women at the ages of 20-40 years old.

Clinical presentation

Most are asymptomatic, although patients with large lesions can present with pelvic pain.

Pathology

They usually occur around the broad ligament and arise from paramesonephric, mesothelial, or mesonephric remnants. They are usually simple cysts (although some authors include paraovarian cystadenomas under the umbrella of paraovarian cysts).

Radiographic features

A paraovarian cyst is easier to recognize if the ipsilateral ovary is demonstrated to be separate from it.

Pelvic ultrasound
  • typically thin-walled and smoothly marginated
  • typically unilocular simple cyst (in ~66%); rarely multilocular (~4%)
  • cyst moves independently of ovary when transducer pressure is applied
  • rarely, a soft tissue nodule in the cyst may indicate the development of a neoplasm
Pelvic MRI

Often seen located close to the ipsilateral round ligament and are often of homogenous signal intensity.

In uncomplicated cases, signal characteristics usually follow that of fluid .

  • T1
    • hypointense
    • can be hyperintense if complicated by hemorrhage
  • T2
    • hyperintense

Other features include

Treatment and prognosis

Paraovarian cysts occasionally can be complicated by rupture, torsion, or hemorrhage. Large or symptomatic cysts often undergo surgical resection. Smaller asymptomatic ones are treated conservatively.

Given a small chance of representing neoplasm, paraovarian cystic lesions may be recommended for follow-up imaging. Societal guidelines differ in this regard.

The 2010 Society of Radiologists in Ultrasound consensus statement recommends follow-up of simple paraovarian cysts in situations similar to that of simple ovarian cysts :

  • 5-7 cm simple cyst in premenopausal women: yearly ultrasound
  • 1-7 cm simple cyst in postmenopausal women: yearly ultrasound
  • >7 cm simple cyst in any age: further imaging (e.g., MRI) or surgical evaluation

In contrast, the American College of Radiology Ovarian-Adnexal Reporting and Data System (O-RADS) for ultrasound, published in 2019, recommends the following :

  • any size simple paraovarian cyst in premenopausal women: no follow-up
  • any size simple paraovarian cyst in postmenopausal women: optional single follow-up study in 1 year
  • nonsimple paraovarian cysts: management dependent on risk stratification as per ovarian criteria

Finally, the American College of Radiology Incidental Findings Committee on adnexal findings on CT or MRI recommends that for paraovarian cysts with characteristic features, further imaging is usually unnecessary .

Differential diagnosis

For an adnexal cystic lesion consider:

Siehe auch:
und weiter:
Assoziationen und Differentialdiagnosen zu Paraovarialzysten: