Fibroids are a very common, non-cancerous growth in the uterus. Fibroids do not turn malignant. Though uterine fibroids can grow quite quickly, it does not mean they’re nasty. Large fibroids also do not indicate malignancy.
There is however, a nasty (malignant and cancerous) tumour of the uterus known as uterine sarcoma – formally known as leiomyosarcoma. This tumour is very rare and is only found in two per thousand cases of hysterectomies. Please note: rapid growth and size of uterine fibroids does not predict sarcoma. A fear of sarcoma should not normally be construed as a reason for a hysterectomy, as a hysterectomy itself is a major operation, with complications and death rates. The American College of Obstetricians and Gynaecologists does not recommend a hysterectomy solely to rule out sarcoma.
Ultrasound cannot reliably diagnose a sarcoma. Advanced MRI (diffusion-weighted imaging DWI) and blood tests (LDH isoenyzmes) might raise suspicion. Continued growth after menopause also raises concern. Failure to shrink following embolisation is another warning sign.
Fortunately, over 97 % of sarcomas are slow-growing. If a particular uterine fibroid remains viable after embolisation, a hysterectomy may be needed to rule out sarcoma. It is important to attend MRI follow-ups after having UFE, to ensure a sarcoma has not been missed.