If the cyst does not rupture these cysts may persist. There may be pain around the middle of a woman's cycle over the ovary which represents the rupture of these cysts, which is a normal and necessary part of a normal cycle. Occasionally, these will bleed and become quite painful, with lower pelvic pain and pain on intercourse. Usually once a cyst is identified it is merely followed to ensure that it does not continue to enlarge. When she went in for her normal ultrasound they discovered that she has several benign cysts within her left ovary.
Cysts form in the ovary every month after puberty.
In pre-puberty females cysts can also form. They are rarely studied since young girls rarely need ultra-sounds. Benign cysts have a different appearance on ultra-sound than cancerous growths. However, the only absolute way is to insert a needle into the cyst. I wouldn't he too concerned.