a mass of muscle and fibrous (= thread-like) tissue that forms inside someone's body, usually inside the uterus (= the part of the body where a baby grows)

In most cases, fibroids are harmless and symptom-free. 绝大多数情况下，纤维瘤无害并且无症状。

During her pregnancy, an ultrasound scan showed she had fibroids. 怀孕期间的一次超声扫描显示她有纤维瘤。