[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Radiology](https://durgical.com/en/radiology/) › [Pelvis, urinary tract and obstetrics](https://durgical.com/en/radiology/areas/pelvis/) › Pelvic ultrasound in gynaecology: cysts, fibroids, torsion

# Pelvic ultrasound in gynaecology: cysts, fibroids, torsion

- Finding

A pelvic scan shows the uterus and ovaries, telling harmless cysts and fibroids apart from torsion and lumps that need a specialist.

Updated Nov 13, 2026

## Key points

- Transvaginal view gives detail; transabdominal gives the overview of large masses.
- Simple anechoic thin-walled cyst in a premenopausal woman: almost always benign.
- Torsion: big oedematous ovary with peripheral follicles and a whirlpool pedicle; flow on Doppler does not exclude it.
- Solid parts with flow, papillary projections or ascites: refer as possibly malignant.
- Fibroid: well-defined hypoechoic whorled myometrial mass with edge shadows.

## What it is

Pelvic ultrasound is the first imaging test in gynaecology. A transabdominal view with a full bladder gives the overview and shows large masses; the transvaginal view gives the detail of the endometrium, myometrium and ovaries. Colour Doppler adds blood flow. Most findings are benign and can be named by their pattern: a simple functional cyst, a haemorrhagic cyst, an endometrioma, a dermoid, or a fibroid. The scan also looks for the urgent pictures, such as an enlarged ovary in torsion or a tubo-ovarian abscess, and for the features that make an adnexal mass suspicious for cancer. MRI is the problem-solving test when ultrasound cannot say what a mass is.

## What it looks like

- Simple cyst: round, anechoic, thin smooth wall, bright posterior enhancement, no solid part and no internal flow; in a premenopausal woman it is usually a follicle or functional cyst.
- Haemorrhagic cyst: fine lacy or net-like internal echoes or a retracting clot that has no flow on Doppler; it usually resolves within weeks.
- Endometrioma: a thick-walled cyst full of uniform low-level «ground-glass» echoes.
- Dermoid (mature cystic teratoma): a bright echogenic nodule or plug, fine bright lines and dots from hair, sometimes a fat–fluid level and shadowing that hides the back of the mass.
- Fibroid (leiomyoma): a well-defined, rounded, usually hypoechoic myometrial mass with a whorled texture, edge shadows and flow around its rim.
- Ovarian torsion: an enlarged, oedematous ovary with follicles pushed to the periphery, often a mass as the lead point, free fluid, and a twisted pedicle («whirlpool sign»).
- Suspicious adnexal mass: solid parts with internal flow, thick or irregular septa, papillary projections, ascites or peritoneal nodules.

## Why it looks that way

- Fluid is anechoic and transmits sound well, so simple cysts are black with a bright band behind them; blood and debris add echoes.
- Fibroids are dense bundles of smooth muscle and fibrous tissue that attenuate sound, which gives the edge shadows and fan-like («venetian blind») shadowing.
- In torsion, twisting first blocks the low-pressure veins and lymphatics, so the ovary swells before arterial flow stops; this is why Doppler flow can still be seen.
- The ovary has a dual blood supply (ovarian artery and a branch of the uterine artery), another reason flow may persist despite torsion.

## Differential and pitfalls

- Normal Doppler flow does not exclude ovarian torsion: the diagnosis is clinical plus an enlarged ovary, and suspicion means surgery.
- A torsed ovary is usually larger than the other one; a normal-sized ovary with normal flow makes torsion much less likely.
- In a woman of reproductive age with pelvic pain, do a pregnancy test first: ectopic pregnancy is in the same differential.
- Locate fibroids by their relation to the cavity (submucosal, intramural, subserosal, pedunculated): submucosal ones cause bleeding and infertility.
- Adenomyosis looks different from fibroids: a globular uterus with asymmetric, poorly defined myometrial thickening and small myometrial cysts, without a separate mass.
- Postmenopausal bleeding: a thin endometrium (about 4 mm or less) makes cancer unlikely; a thicker or irregular one needs sampling.
- A simple cyst in a postmenopausal woman is usually benign but follows a guideline-based follow-up; any solid part changes the picture.

## Next step

- Suspected torsion (sudden pain, vomiting, enlarged ovary): call gynaecology for laparoscopy now; do not wait for a further scan.
- Haemorrhagic or functional-appearing cyst: repeat scan in about 6 to 12 weeks, ideally after a period, to confirm resolution.
- Adnexal mass with suspicious features or ascites: refer to gynaecologic oncology; MRI if ultrasound is indeterminate.
- Fever, pelvic pain and a complex adnexal collection: treat as tubo-ovarian abscess and involve gynaecology for antibiotics or drainage.
- Postmenopausal bleeding with a thickened endometrium: refer for endometrial sampling.

## Test yourself

Think of the answer, then tap the question to see it.

## Why can colour Doppler show blood flow in an ovary that is torsed?

Twisting blocks the veins first, and the ovary has a dual arterial supply, so arterial flow can persist; flow does not exclude torsion.

## What does a dermoid cyst typically look like on pelvic ultrasound?

A cyst with a bright echogenic plug, fine bright lines and dots from hair, sometimes a fat–fluid level, and shadowing that hides its back wall.

## Which adnexal ultrasound features raise concern for malignancy?

Solid components with internal flow, thick or irregular septa, papillary projections, ascites and peritoneal nodules.

## How is a haemorrhagic cyst told apart from a solid ovarian mass?

Its internal lacy echoes or retracting clot have no flow on colour Doppler, and it shrinks or resolves on a repeat scan weeks later.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/radiology/pelvic-ultrasound-in-gynaecology-cysts-fibroids-torsion/)

## Elsewhere in DurgiPedia

- [Gynecologic examination: speculum and bimanual exam](https://durgical.com/en/clinical-exam/gynecologic-examination-speculum-and-bimanual-exam/)
- [Gynecologic and obstetric history](https://durgical.com/en/clinical-exam/gynecologic-and-obstetric-history/)

## Connections

## Related 5

- [First-trimester ultrasound: intrauterine pregnancy, dating and ectopic](https://durgical.com/en/radiology/first-trimester-ultrasound-intrauterine-pregnancy-dating-and-ectopic/)
- [Ultrasound: echogenicity, probes, Doppler and artefacts](https://durgical.com/en/radiology/ultrasound-echogenicity-probes-doppler-and-artefacts/)
- [CT of the acute abdomen: what to look for](https://durgical.com/en/radiology/ct-of-the-acute-abdomen-what-to-look-for/)
- [Imaging in suspected appendicitis](https://durgical.com/en/radiology/imaging-in-suspected-appendicitis/)
- [MRI: T1, T2, FLAIR and diffusion](https://durgical.com/en/radiology/mri-t1-t2-flair-and-diffusion/)

## Related conditions 9

- [Ovarian cyst](https://durgical.com/en/conditions/ovarian-cyst/)
- [Ovarian torsion](https://durgical.com/en/conditions/ovarian-torsion/)
- [Uterine fibroids (leiomyomas)](https://durgical.com/en/conditions/uterine-fibroids/)
- [Adenomyosis](https://durgical.com/en/conditions/adenomyosis/)
- [Endometriosis](https://durgical.com/en/conditions/endometriosis/)
- [Polycystic ovary syndrome](https://durgical.com/en/conditions/polycystic-ovary-syndrome/)
- [Pelvic inflammatory disease](https://durgical.com/en/conditions/pelvic-inflammatory-disease/)
- [Ovarian cancer](https://durgical.com/en/conditions/ovarian-cancer/)
- [Endometrial cancer](https://durgical.com/en/conditions/endometrial-cancer/)

[← All of radiology](https://durgical.com/en/radiology/)

Educational content; it does not replace a radiologist's report and is not a clinical instruction. Each study is ordered on the patient's assessment and your institution's protocols.

Sources: [Transvaginal Ultrasonography](https://www.ncbi.nlm.nih.gov/books/NBK572084/) (StatPearls (NCBI Bookshelf), 2022); [Ovarian Cyst](https://www.ncbi.nlm.nih.gov/books/NBK560541/) (StatPearls (NCBI Bookshelf), 2023); [Ovarian Torsion](https://www.ncbi.nlm.nih.gov/books/NBK560675/) (StatPearls (NCBI Bookshelf), 2023); [Uterine Leiomyomata](https://www.ncbi.nlm.nih.gov/books/NBK546680/) (StatPearls (NCBI Bookshelf), 2025).

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/radiology/pelvic-ultrasound-in-gynaecology-cysts-fibroids-torsion/