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Female pelvic imaging: ovarian masses, endometriosis, uterine anomalies and tumours
US is the first test for a pelvic mass, and O-RADS recognises classic benign lesions (haemorrhagic cyst, endometrioma, dermoid); MRI characterises an indeterminate lesion (fat, blood, fibrous tissue) and sets the local extent of cervical cancer.
Why it matters in the exam
Classic benign lesions on US: simple cyst (smaller than 3 cm in reproductive age is a normal follicle); haemorrhagic cyst — a fine lacy network or retracting clot, without internal flow; endometrioma — homogeneous low-level echoes ("ground glass"); dermoid — an echogenic "plug" with shadow and lines and dots. On MRI: endometrioma bright on T1 with "shading" on T2; dermoid contains fat that disappears with fat suppression; fibroma and thecoma — dark on T1 and T2. Deep endometriosis: fibrotic plaques dark on T2 with bright T1 foci, and "kissing" ovaries. Ovarian torsion: a large oedematous ovary with peripheral follicles and a whirlpool sign — Doppler flow does not exclude torsion.
Uterine anomalies (ESHRE/ESGE): septate uterus — the external fundal contour is normal or slightly indented, and it is the anomaly most associated with pregnancy loss and is corrected hysteroscopically; bicornuate uterus — a deep external fundal cleft; unicornuate uterus — associated with ipsilateral renal agenesis. MRI or three-dimensional US separate them; HSG shows only the cavity. Adenomyosis — a thickened junctional zone, 12 mm or more, with small bright foci. Fibroids — dark on T2 and well defined, with various types of degeneration.
Cervical cancer: FIGO 2018 allows imaging for staging; MRI is best for local extent — parametrial invasion appears as disruption of the dark T2 stromal ring. Endometrial cancer: MRI assesses depth of myometrial invasion (less or more than half) and cervical involvement; FIGO stage III — invasion of serosa or adnexa (IIIA), vagina or parametrium (IIIB), or lymph nodes (IIIC). Ovarian cancer: CT of the chest, abdomen and pelvis for peritoneal spread. Ectopic pregnancy: an empty uterus with an adnexal mass and free fluid, in the context of β-hCG.
Key points
- O-RADS: haemorrhagic cyst, endometrioma, dermoid — classic benign.
- Endometrioma — bright on T1 with T2 shading.
- Torsion — oedematous ovary; flow does not exclude it.
- Septate versus bicornuate — by the external fundal line.
- Cervix — MRI for the parametrium.
Summary table
| Lesion | US | MRI | Management |
|---|---|---|---|
| Haemorrhagic cyst | Fine network, retracting clot, no flow | Bright on T1 | Short follow-up; resolves |
| Endometrioma | Homogeneous low-level echoes | Bright on T1, shading on T2 | By symptoms and fertility |
| Dermoid | Echogenic plug with shadow | Fat that disappears with fat suppression | Resection by size |
| Fibroma | Solid hypoechoic | Dark on T1 and T2 | Benign |
| Solid mass with flow | Solid areas and flow | Early enhancement | Refer to a gynaecological oncologist |
A free exam question
בבדיקה גינקולוגית נצפו שני צווארי רחם. איזה ממצא ניתן למצוא בסבירות גבוהה? (the question as examined, in Hebrew)
- א. ירידה ברזרבה שחלתית
- ב. ציסטה ע״ש מורגני
- ג. חסר בכליה ימין
- ד. קרן רחמית רודימנטרית
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Sources
- ACR O-RADS US Risk Stratification and Management System, version 2022 — Classic benign lesions and categories
- FIGO Staging of Cancer of the Cervix Uteri, 2018 — Use of imaging in staging
- ESHRE/ESGE Classification of Female Genital Tract Congenital Anomalies, 2013 — Uterine anomalies
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.