A rapid increase in size (an increase of 2-4 weeks size on examination by the same examiner, done 2-3 months apart, or an increase of 6 weeks size over one year) has been thought to be associated with malignancy (sarcoma). Fortunately, this does not seem to be the case. In one study of over 1300 women operated on for presumed fibroids the incidence of uterine sarcoma was only 0.23%. Of the 371 women operated on specifically for "rapidly growing fibroids" only 0.27% were found to have sarcoma. Leiomyosarcoma, the malignancy that sounds similar to fibroids (leiomyomata), is a de novo tumor that does not represent degeneration of a preexisting benign fibroid. These tumors more typically arise in postmenopausal women (the 5th or 6th decade of life), usually associated with a pelvic mass, abnormal bleeding and pelvic pain. The incidence has been estimated at <1%, closer to 0.1% in premenopausal women. There is no screening test that can reliably detect this malignancy. The other gynecologic malignancies of concern include cervical, endometrial, and ovarian cancer. Since UFE is a uterine sparing treatment it is important to exclude these diagnoses prior to the procedure. The Pap smear is used to screen for cervical cancer. An endometrial biopsy is for excluding endometrial cancer and other non-fibroid causes of abnormal uterine bleeding. Ultrasound and MRI are both helpful in evaluating for ovarian cancer, especially when large fibroids obscure evaluation of the ovaries on physical examination.