Uterine fibroids are common benign gynecological tumors that do not become cancerous, but in severe cases, they may malign into uterine sarcoma, and the possibility of malignant transformation into uterine sarcoma is relatively small, and if they do, they may metastasize to other parts of the body through bloodstream and lymph. For uterine sarcoma, it may generally manifest as abnormal uterine bleeding, abdominal pain, increased vaginal discharge, and abdominal masses. For example, in some patients, if the fibroid grows rapidly and large, abdominal masses or uterine enlargement, or accompanied by ascites, are precursors to malignancy. If a woman’s fibroids do not shrink but grow after menopause, she should be alert to the occurrence of uterine sarcoma, and early surgery is recommended. In conclusion, fibroids are a common benign gynecological tumor, and treatment is related to the size of fibroids, abnormal menstruation and age, etc. In most cases, they do not become malignant. However, if the fibroids do not decrease in size after menopause but increase in size, or if they grow rapidly, abdominal pain, abnormal uterine bleeding or ascites may be a precursor to malignancy or cancer.