Dermoids always need to be removed because they contain fat, hair, nails, etc. These components can cause infection
if they rupture
. Any complex cyst (dermoids are complex) that reach 5cm or larger need surgical removal intact. This is best performed by a gynecologic oncologist. Most complex cysts do turn out to benign, but, any complex cyst has a "chance" of being malignant. So, it is important to get prompt care and make sure all is well.