There is a difference between a cyst and a follicle, the main difference being that a follicle is formed in the ovary, whereas a cyst means a cystic blister, and it has more possibilities. If a follicle is present in the ovary at the time of ultrasound, which may include normal follicles, cysts, etc., then further testing is required. If at the time of ultrasound examination, it is not certain that what is present in the ovary is a follicle, it is necessary to differentiate it in relation to the size of the follicle. If the cyst is physiologic, it may recover naturally during the next menstrual cycle. If it is a pathologic cyst, it may not go away on its own while continuing to grow in size. For physiological ovarian cysts, no special treatment is needed, but for pathologic ovarian cysts, if the diameter exceeds 5cm, they need to be treated by surgery.