A fibroid cyst is a type of common, non-cancerous tumor that is most often found in the uterus. Most cases are slow growing and do not cause any symptoms, and only a small percentage of cases will require medical treatment. Fibroid tumors are categorized according to where they grow in the uterus. Some studies suggest that up to 75% of women will develop fibroid cysts during their lifetime.
Although the term "fibroid cysts" is often used, they are not technically cysts. A cyst contains air, fluid, or a semi-solid material, while fibroid cysts are made up of fibrous material, which makes them tumors. As a result, they are also referred to as "fibroid tumors," "fibrolids," "myomas," or simply "fibroids." Varying in size from about 0.04 inches (1 mm) to about 8 inches (20 cm) or more, a fibroid tumor can grow as one nodule or in a cluster.
The cause of fibroids has not yet been determined, but appears to be linked to estrogen production in a woman's body. These tumors only seem to develop during the reproductive years, and existing fibroids may even start to shrink after menopause. They can grow quickly during pregnancy when estrogen production and blood flow to the uterus increases, but they usually do not cause complications.
Fibroid tumors are quite common among women who are at a reproductive age, particularly those in their 30s and 40s. Many cases go undetected when there are no symptoms, and they are not always found during an ultrasound. In addition to being more at risk while at a reproductive age, women whose mothers or sisters had fibroids, and women of African descent are generally more at risk for the condition.
Most women who have fibroid tumors have no symptoms at all. In women who do have symptoms, some more common ones include pain, excessive bleeding during menstrual cycles, constipation or bloating, and changes in urinary frequency. Infertility is not a common result of fibroids, but they do account for a small percentage of infertility cases. Where the cyst is located can influence which symptoms a woman experiences.
Types of Fibroid Cysts
There are three types of fibroid tumors, determined by where the fibroid grows in the uterus:
- Intramural fibroids, which grow in the uterine wall, are the most common type. They can cause the uterus to swell, and sometimes protrude either into or outside of the uterus.
- Submucosal fibroids, also called submucous fibroids, are usually the most likely to cause noticeable symptoms. These fibroids are found within the lining of the uterus, and may extend inside the uterus itself. As a result, submucosal fibroids can cause heavy bleeding during menstruation.
- Subserosal fibroids, also called subserous fibroids, grow on the outside of the uterus. These fibroids often cause the fewest symptoms, but can grow to be very large. Some subserosal fibroids become so large that a woman may look up to six months pregnant.
Usually, a fibroid cyst will not require treatment unless a woman is experiencing symptoms. In the past, hysterectomies were common practice for curing fibroid tumors, but alternative treatments have since been developed. These newer treatments include surgery to remove the tumor, medication to control symptoms, ultrasound treatments to destroy the fibrous tissue, or an injection of polyvinyl alcohol beads to block blood flow to the fibroids.