The differences between ovarian cysts and follicles are as follows: 1. Follicles are growing, normally at a rate of 1.5-2mm per day, and when they reach dominance they may rupture and expel eggs at any time, with symptoms of local collapse of the follicle wall, whereas ovarian cysts do not grow at a rate of 1.5-2mm per day. 2. Ovarian cysts tend to be larger than 5cm in diameter, whereas follicles tend to be smaller than 2cm in diameter. 3. Follicles shrink with ovulation, while ovarian cysts do not shrink.