Hemorrhagic Ovarian Cyst: Ultrasound Appearance, Endometrioma Differential, O-RADS and Follow-up
The reticular pattern and retracted clot of a hemorrhagic ovarian cyst, how to tell it from an endometrioma, the O-RADS category and follow-up by size and menopausal status.
LaudárioUltrasound reports in practice
This article is part of the guide Gynecologic ultrasound: the complete guide, from uterus to ovaries.
A typical hemorrhagic ovarian cyst appears as a unilocular cyst with no internal vascularity and a reticular fibrin pattern or retracted clot, and in premenopausal patients it is O-RADS 2 when it measures less than 10 cm. It is a common benign finding in reproductive age, but it can be mistaken for an endometrioma or a solid lesion. The report must state why the cyst is typical, because that is what avoids unnecessary workup.
Hemorrhagic ovarian cyst: the typical appearance
- Reticular pattern: fine interlacing fibrin strands with no Doppler flow.
- Retracted clot: solid-looking area with no flow and concave borders. A true mural nodule usually has a convex border.
- Unilocular with no internal vascularity: both are part of the O-RADS definition.
- Acute phase: the cyst may be filled with low-level echoes and mimic a solid lesion. Preserved through-transmission and negative Doppler help.
At least one of the two patterns (reticular or retracted clot) must be present. Without them, the cyst is not classified as a typical hemorrhagic cyst.
Differential with endometrioma
| Typical hemorrhagic cyst | Typical endometrioma | |
|---|---|---|
| Content | Reticular or retracted clot | Homogeneous low-level echoes (ground glass) |
| Locules | Unilocular | Up to 3 locules |
| Wall | Thin | Smooth; may have punctate echogenic foci |
| Internal flow | Absent | Absent |
| Course | Usually regresses within weeks | Persists |
The two can look alike, especially when a hemorrhagic cyst is filled with fine echoes. In that doubt, short-term follow-up settles it: the hemorrhagic cyst regresses or changes, and the endometrioma stays. O-RADS gives 2 to 3 months; other references cite 6 to 12 weeks.
Other differentials: dermoid (hyperechoic nodule, shadowing, echogenic lines and dots) and neoplasm (solid component with flow, vascularized septa, irregular wall, ascites).
O-RADS and follow-up
Under O-RADS US v2022, both are classic benign lesions: O-RADS 2 below 10 cm and O-RADS 3 at 10 cm or more.
| Setting | Typical hemorrhagic cyst | Typical endometrioma |
|---|---|---|
| Premenopausal | Up to 5 cm: no management. Above 5 and below 10 cm: ultrasound in 2 to 3 months | Below 10 cm: if not excised, ultrasound in 12 months |
| Early postmenopausal (under 5 years) | Below 10 cm: ultrasound in 2 to 3 months, ultrasound specialist or MRI | Below 10 cm, at initial exam: same options; then, if not excised, ultrasound in 12 months |
| Late postmenopausal (5 years or more) | Should not occur: recategorize using lexicon descriptors | As above |
In all cases, gynecology input is added as needed. O-RADS notes a higher malignancy risk in endometriomas after menopause and when present for more than 10 years.
What the report should include
- Side, measurements and internal pattern (reticular or retracted clot).
- Absence of internal vascularity on Doppler.
- O-RADS category, with the menopausal status considered.
- Follow-up according to size and menopausal status.
- Free fluid and its appearance, in a patient with pain.
Common mistakes
- Calling it a "complex cyst" without describing the pattern.
- Reporting a retracted clot as a mural nodule without using Doppler.
- Requesting follow-up for a typical hemorrhagic cyst up to 5 cm in a premenopausal patient.
- Keeping the hemorrhagic label in late postmenopause.
- Labeling a cyst with fine echoes as an endometrioma at first exam without considering follow-up.
See also our articles on O-RADS, ovarian torsion and deep endometriosis mapping.
How Laudário helps
In the female pelvis templates of Laudário, on the ovaries tab:
- Typical hemorrhagic cyst option, with reticular or retracted clot internal pattern.
- Measurements and volume in the lesion fields, with the report sentence built from them.
- O-RADS category assigned by the largest diameter: 2 below 10 cm and 3 from 10 cm.
- Typical endometrioma option alongside it, to keep the differential clear.
Try it for 15 days free, no credit card required.
References
- American College of Radiology. O-RADS US v2022 Assessment Categories.
- Strachowski LM, et al. O-RADS US v2022: An Update from the American College of Radiology's Ovarian-Adnexal Reporting and Data System US Committee. Radiology 2023;308(3):e230685.
- Radiology Assistant. Roadmap to evaluate ovarian cysts.
Physician with an RQE specialty registration in general ultrasound. Writes on the Laudário blog about reports, classifications and standardization. Who writes and how.
Educational content for healthcare professionals. It does not replace clinical judgment or the guidelines adopted by your service. Editorial policy.