Diagnostic Ultrasound - Abdomen and Pelvis

Cystic Adnexal Mass
□ Hemorrhagic cyst or endometrioma may be
mistaken for simple cyst
○ Solid Lesion (Mimic)
– May appear as anechoic cyst if gain set too low and
color Doppler not used
○ Nabothian Cyst
– Can be confused for adnexal cyst if location in cervix is
not noted
• Adnexal Torsion
○ Rare for adnexal torsion to present as anechoic cyst
○ Cyst 5-10 cm in size can act as lead point for torsion
○ Ipsilateral pain out of proportion to size of cyst suggests
torsion
○ Blood flow analysis typically not helpful, because
anechoic cysts do not demonstrate flow
Alternative Differential Approaches
• Multiple cysts
○ Multiple physiologic cysts
○ Hydrosalpinx folded on itself
○ Peritoneal inclusion cyst
○ Ovarian inclusion cysts
○ Theca lutein cysts
○ Hyperstimulated ovaries
• Bilateral cysts
○ Peritoneal inclusion cyst
○ Theca lutein cysts
○ Hyperstimulated ovaries
○ Hydrosalpinx
○ Cystadenoma
• Pregnant patient
○ Corpus luteum
○ Serous cystadenoma
○ Theca lutein cysts
○ Hyperstimulated ovaries
Society of Radiologists in Ultrasound Consensus
Criteria for Reporting of Simple Cyst
• Premenopausal
○ ≤ 3 cm: Best to refer to these as dominant follicles and
not necessary to report
○ > 3 and ≤ 5 cm: Mention in the report; state almost
certainly benign; no follow-up needed
○ > 5 and ≤ 7 cm: 1-year follow-up
○ > 7cm: Surgical evaluation
– Some seemingly simple cysts may have complex
features missed by US when over 7.5 cm
• Peri- or postmenopausal
○ ≤1 cm: Benign; no follow-up; discretion of radiologist
wether to mention in report
○ >1 and ≤7 cm: Almost certainly benign; 1-year follow-up
○ >7 cm: Surgical evaluation
American College of Radiology Incidental Cystic
Adnexal Findings Detected at CT/MR
• Benign appearing cyst (defined as oval/round, unilocular,
uniform fluid attenuation/signal, thin wall, no solid area or
mural nodule, < 10 cm maximum diameter)
○ Premenopausal
– ≤ 5 cm: No follow-up
– > 5 cm: US follow-up in 6-12 weeks
○ Early postmenopausal
– ≤ 3 cm: No follow-up
– > 3 and ≤ 5 cm: US follow-up in 6-12 weeks
– > 5 cm: US
○ Late postmenopausal
– ≤ 3 cm: Benign, no follow-up
– > 3 cm: US
– Note: Higher threshold of 3 cm was adopted which
decreases sensitivity; some groups may want to adopt
1 cm similar to SRU guidelines
SELECTED REFERENCES
1. Patel MD et al: Managing incidental findings on abdominal and pelvic CT and
MRI, part 1: white paper of the ACR Incidental Findings Committee II on
adnexal findings. J Am Coll Radiol. 10(9):675-81, 2013
2. Levine D et al: Management of asymptomatic ovarian and other adnexal
cysts imaged at US: Society of Radiologists in Ultrasound Consensus
Conference Statement. Radiology. 256(3):943-54, 2010
Differential Diagnoses: Female Pelvis
Follicular Cyst
Follicular Cyst
(Left) Longitudinal
endovaginal US in a 27-yearold
woman shows a 2.5 cm
anechoic cyst ſt in the left
ovary consistent with a
follicular cyst, a normal
finding. These do not have to
be mentioned in the radiology
report as it may elicit
inappropriate follow-up and
patient anxiety. (Right)
Endovaginal US in a
premenopausal asymptomatic
woman shows thin-walled
anechoic ovarian cyst,
measuring 3.5 cm compressing
adjacent ovarian parenchyma
. This is typical of a
follicular cyst.
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