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 visualised 12-24 hours before ovulation 3.

It comprises of 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

  • it may be seen as a small anechoic cyst (or group of cysts) around a dominant follicle
  • septated ovarian cyst: stage of the menstrual cycle may help differentiate

The word "cumulus oophorus" literally means "heap of eggs".

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Article information

rID: 42514
System: Gynaecology
Synonyms or Alternate Spellings:

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