Category B - full version without watermark 720x576 (check terms and conditions at www.teledesign.de) The embed version with watermark is free of charge. - Description: At onset of puberty a follicle forms once a month within the ovary and an egg matures. Once a certain size is reached, the follicle bursts and sets the egg cell free. This egg cell travels to the womb and there settles in the mucosa. If no fertilization takes place menstruation is triggered and the uterine mucosa shed. Sometimes it happens that a follicle keeps growing. In this case a cyst will develop. It hence arises from normal ovary function. These follicle cysts are relatively common but largely benign. Mostly they are no larger than 6 cm and resolve spontaneously in more than 90% of cases.