Update: We are now collecting Disclosures from all users who edit content. You will be prompted to update these when you next edit content or you can complete your disclosures at any time in your user profile. This has been reflected in an updated terms-of-use.

Cumulus oophorus

Last revised by Mr. Dennis Odhiambo Agolah on 06 Aug 2022

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

  • 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​

ADVERTISEMENT: Supporters see fewer/no ads

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.