Cumulus oophorus
Cumulus oophorus refers to an appearance in the ovary in which multiple granulosa cells enlarge around a developing oocyte. These support cells ("cumulus cells") serve multiple functions in the maturation of the oocyte. They may occasionally be seen during a pelvic ultrasound, and should not be confused with a pathological finding.
60-65% of the time a cumulus oophorus is visualized 12-24 hours before ovulation 3.
It comprises a collection of the cells in a mature follicle that protrude into the cavity of the follicle. It is a sign of imminent ovulation, but its absence has little significance in predicting the maturity of the oocyte.
On ultrasound, the cumulus oophorus appears as a cyst along the wall of the dominant follicle
Radiographic features
Ultrasound
- it may be seen as a small anechoic cyst (or group of cysts) around a dominant follicle
Differential diagnosis
- septated ovarian cyst: the stage of the menstrual cycle may help differentiate
Related Radiopaedia articles
Ultrasound - gynaecology
- ultrasound (introduction)
-
gynaecologic ultrasound
- acute pelvic pain
- chronic pelvic pain
-
uterus
- endometrium
- myometrium
- Mullerian duct anomalies
-
ovaries
- ovarian follicle
- ovarian torsion
- pelvic inflammatory disease
- ovarian cysts and masses
- paraovarian cyst
- polycystic ovaries
- ovarian hyperstimulation syndrome
- post-hysterectomy ovary
- cervix
- fallopian tube
- other
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