Adnexal Lesions: Recommendations for incidental lesions on CT or MRI

Authors: Lauren Roller, MDKrista Suarez Weiss, MDAtul Shinagare, MD

Date: February 23, 2021

Mass Characteristics

Simple-appearing cyst
Characteristic imaging features (not simple appearing cyst)
Uncertain diagnosis

Size Largest dimension
Technical Considerations

Limited Assessment on CT/MRI

  • Low SNR
  • Artifact
  • Lack of contrast
  • Incomplete anatomic coverage

Fully Characterized by MRI:

  • T2W images, pre- and post-contrast T1W images
  • Full anatomic coverage in at least 2 planes
Known or presumed menopausal status

If unknown:

  • > 50 years is presumed post-menopausal
  • < 50 years presumed pre-menopausal
  • Pre-menarchal women
  • Lesions ≤ 1 cm
  • Lesions that are unchanged in > 2 years
  • Women at high genetic risk for ovarian malignancy
  • Women with symptoms potentially related to the mass
  • Lesions previously characterized by US or MRI


  • Round or oval
  • Smooth, imperceptible or thin walls
  • No septations or solid component
  • Fluid signal on MRI

Age ≤ 3 cm >3-≤ 5cm >5 cm
Pre-menopausal No follow up No follow up Further imaging**
Post-menopausal No follow up Further imaging**

**Further Imaging:

If fully characterized by MRI:
If limited assessment US to characterize
If adequate assessment but not fully characterized by MRI US follow up in 6-12 months
Pre-menopausal: ≤ 7 cm No further imaging
> 7 cm US follow up in 6-12 months
Post-menopausal: ≤ 5 cm No further imaging
> 5 cm US follow up in 6 -12 months
Adnexal Mass Pre-menopausal (or age < 50 yrs if unknown) Post-menopausal (or age > 50 yrs if unknown)
Hemorrhagic cyst < 5 cm: no further imaging > 5 cm: follow up US in 2-3 months US or MRI to characterize
Para-ovarian cyst Usually further imaging is unnecessary; clinical management
Peritoneal inclusion cyst
Simple hydrosalpinx
Ovarian fibroma
Uterine leiomyoma
Endometrioma Usually gynecologic management; may require follow-up imaging
Suspected malignancy Prompt US or MRI to characterize


Adnexal masses without simple or characteristic imaging features should be evaluated promptly with US or MRI for further characterization

  • US usually first imaging choice
  • MRI may be superior for lesions >10 cm

Impression: Incidentally detected <Description of adnexal lesion>.

Recommendation: No further imaging is necessary./Follow-up with pelvic ultrasound at 6-12 months is recommended./Further evaluation with pelvic ultrasound is recommended.

Reference: ACR White Paper on Incidental Adnexal Findings on CT and MRI (Patel et al. JACR 2020;17(2):248-254)

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