Practical Approach to Ovarian Masses - Part 2
The Importance of Unilocularity

Take Home Points

why is unilocularity so important

• All non-neoplastic cysts are unilocular. The vast majority of ovarian masses are non-neoplastic.
  • Therefore, if it is not unilocular it is not a nonneoplastic cyst
• Looking at the literature, unilocularity has a 98.5% pos. predictive value for a lesion being benign
• This includes lesions > 10 cm although some of these will be pathologically borderline tumors
• So, you find a lesion... you decide it's unilocular.... you can conclude that it is almost invariably benign.
  • (Note: It could still be a neoplasm, but a benign neoplasm.)

because this is so important...

... it will behoove you to diligently examine the lesions to ensure unilocularity

what does unilocular mean?

• No septations with a cystic lesion
• Can have small excrescences and echogenic fluid and still be unilocular
  • Lesions with these characteristics may require additional imaging (see following lecture sections), but are still highly likely to be benign