Leiomyomas (fibroids) are common findings within the uterus – more than 25% of women over the age of 30 have fibroids. Leiomyomas and pregnancy are the most common causes of enlarged uteri. It is common for affected patients to have multiple leiomyomas. Depending of their location within the muscular wall of the uterus, they are classified as submucosal, intramural, and subserosal. Some fibroids are pedunculated, and can appear as extrauterine masses.

The majority of leiomyomas do not cause symptoms, but the likelihood of causing symptoms increases with the size of the fibroids. The submucosal variety may cause menorrhagia or menometrorrhagia. Leiomyomas may cause pain, likely due to mass effect within the pelvis, or to hemorrhage within the fibroids. Large fibroids may outgrow their arterial supply and develop central necrosis. Infrequently the pedunculated leiomyomas undergo torsion.

Leiomyomas are well demonstrated on CT imaging. They distort the normal contour of the uterus and may exhibit mass effect on surrounding structures. Their attenuation is that of soft tissue, and enhances like the rest of the uterus. The attenuation of fibroids that have central necrosis is decreased. Calcification of fibroids is a common finding. MRI, with its multiplanar images and superior soft tissue contrast, is the study of choice for the leiomyomas that are not adequately imaged on ultrasound or CT.

Most fibroids do not require any treatment. For those that do, excision of individual leiomyomas, or hysterectomy, are surgical options. Uterine artery embolization is an interventional procedure that is becoming more popular due to its minimal invasiveness and high success rate.