Ovarian cyst

Ovarian cysts are commonly encountered in gynaecological imaging, and vary widely in aetiology, from physiologic, to complex benign, to neoplastic.

Small cystic ovarian structures should be a considered normal ovarian folliclefollicles unless the patient is pre-pubertal, post-menopausal, pregnant, or the mean diameter is greater than 25 mm>3.0 cm.

Pathology

Types of cysts

• physiological cysts: :meanmean diameter < 25 mm≤3.0 cm
  • ovarian follicle
  • corpus luteum
• functional cysts (can produce hormones):
  • follicular cysts of the ovary (oestrogen): > 25 mm >3.0 cm
  • corpus luteum cysts (progesterone)
  • theca lutein cyst: gestational trophoblastic disease
  • complications in functional cysts:
    • haemorrhage: see haemorrhagic ovarian cyst
    • enlargement
    • rupture
    • torsion
• other cysts:
  • multiple large ovarian cysts in ovarian hyperstimulation syndrome
  • post-menopausal cyst: serous inclusion cysts of the ovary
  • polycystic ovaries
  • ovarian torsion
  • ovarian cystic neosplasms

The risk of malignancy in a simpleSimple ovarian follicular cysts

• anechoic
• intraovarian or exophytic
• imperceptible wall
• posterior acoustic enhancement (may not be as obvious with harmonic or compound imaging)
• visible far wall

A cyst on ultrasoundmay become large enough to obscure the ovary from which it is low and according to once study was ~ 2% ²arising.

Treatment and prognosis

Large

• large (>3 cm) or symptomatic cyst oftencysts may undergo surgical resection.
• smaller asymptomatic onescysts are treated conservatively.

Follow-up guidelines

According to a consensus statement by the society of radiologists in ultrasound³, for simple ovarian cysts with no suspicious features on ultrasound, current follow-up guidelines state:

In women of reproductive age:

• ≤ 3≤3 cm
  • normal physiologic findingsfinding; at the discretion of the interpreting physician whether or not to describe them in the imaging report-do
  • do not need follow-up
• &gt;3;3 and ≤5≤5 cm
  • should be described in the imaging report with a statement that they are almost certainly benign-do
  • do not need follow-up
• &gt; 5;5 and ≤7≤7 cm
  • should be described in the imaging report with a statement that they are almost certainly benign-yearly
  • increased risk of ovarian torsion ⁴
  • yearly follow-up with ultrasound recommended
• &gt; 7;7 cm
  • may be difficult to assess completely with ultrasound and  further further imaging with MR or surgical evaluation should be considered.

In post-menopausal women :

• ≤ 1≤1 cm
  • are clinically inconsequential; at the discretion of the interpreting physician whether or not to describe them in the imaging report-do
  • do not need follow-up
• &gt; 1;1 and ≤ 7≤7 cm
  • should be described in the imaging report with statement that they are almost certainly benign-yearly
  • yearly follow-up, at least initially, with ultrasound recommended
  • some practices may opt to increase the lower size threshold for follow-up from 1 cm to as high as 3 cm.
  • one may opt to continue follow-up annually or to decrease the frequency of follow-up once stability or decrease in size has been confirmed.
  • cysts in the larger end of this range should still generally be followed on a regular basis. 
• &gt; 7;7 cm
  • since these may be difficult to assess completely with ultrasound-further, further imaging with MRMRI or surgical evaluation should be considered

See also

• fetal ovarian cyst
• paraovarian cyst
• ruptured ovarian cyst