9 yr old with abnormal vaginal bleeding

My daughter has had vaginal spotting for the last 13 months.  Her Pediatrician sent us to a Urologist who did a scope procedure, but found nothing abnormal.  Blood test results are in range for her age, hormone level is good so Dr. said the uterus isn't stimulated to cause the bleeding.  Pediatrician referred my daughter to Ped Endocrinologist who suspected a lesion inside the labia, but I have not seen bleeding from any lichen, but from the vaginal opening.  Uterus and ovaries are the correct size for this age, but there are small cysts on both ovaries.  Ped Endo doesn't seem concerned because no large cysts or tumors can be seen from ultrasound.  A transvaginal ultrsound has not been performed.  Can you offer me any advice?