A follicular cyst is the most common type of functional ovarian cyst. It develops when a follicle that was supposed to release an egg during ovulation fails to rupture and instead continues to accumulate fluid and enlarge. On ultrasound, a follicular cyst appears as a simple, thin-walled, anechoic, round or oval structure within the ovary, typically measuring between 2.5 and 10 centimeters. These cysts are almost always benign and usually resolve spontaneously within one to three menstrual cycles. A follow-up ultrasound in 6 to 8 weeks can confirm resolution. Follicular cysts are so common that they are considered a normal physiological occurrence in women of reproductive age.
Sonography Term