Having gone through something similar . The radiologist is unable to make a proper diagnosis with only an ultra sound. I had several and the ultra sound only indicated that something growing or is not typical. Due to the age of your daighter, the fibroid size and aggravating symptoms she is having , I believe the radiologist is just making sure it isn't minimized to " just a fibroid" . An MRI or CT scan will provide more definitive information and it's critical that she is seen by a gyno oncologist. Until the mass is actually removed you can't really know what it is. In Regards to her uterus looking normal I believe it's to indicate that the tumor isn't part of her uterus... My final thought is there is a lot of urgency if it is a Leiomyosarcoma, particularly if it is fast growing .. mine went from 10 to 15 cm in less than 3 months . In the final week before they removed everything I was on morphine, unable to walk or get up without assistance. You will have to be strong advocates. Best wishes