Published: Thu, March 09, 2017
World | By Tasha Manning

Uterine Fibroid Embolization - Fibroids Background Information

Uterine Fibroid Embolization - Fibroids Background Information

All women are at risk of getting fibroids. Uterine fibroids are the most common tumors of the female genital tract. They occur in 20 to 25% of women of childbearing age. The presence of fibroids is the most common reason for a woman to have a hysterectomy in this country, totaling approximately 200,000 each year. In addition, many patients suffer from fibroids but never undergo hysterectomy.

African-Americans are as many as 3.2 times as likely to develop fibroids as Caucasians. There is some variation among other racial groups. The reason for this increased risk is not known, although genetic variability is presumed to be a significant factor. While fibroids may appear in patients in their twenties, most patients do not have any symptoms until their late thirties or forties.

What causes fibroids? The cause of fibroid development is not known. Leiomyomas appear after menarche (beginning of menstruation in adolescence) and regress after menopause, which suggests that the development of fibroids is dependent on the presence of hormones (primarily estrogen). But the triggering event for the development of the fibroid is not known and the interaction of the various hormones and growth factors likely to be involved is not well understood.

Once fibroids appear, their growth rate is also dependent on estrogen, progesterone and possibly other hormones. Growth rates vary greatly among women and the exact cause of this variability is not known, making the prediction of the behavior of fibroids very difficult.

Symptoms Most leiomyomas do not cause symptoms. While 25% of women develop fibroids during their lives, only 10 to 20% of these women have symptoms. Therefore, only a minority of women ever require treatment.

How fibroids cause abnormal bleeding is not known. Fibroids are believed to alter muscular contraction of the uterus, which may prevent the uterus from controlling the degree of bleeding during a patient's period. In addition, it has been shown that fibroids compress veins in the wall of the uterus. This results in dilation of the veins of the uterine lining. As the pressure in these veins increases, the lining of the uterus becomes engorged. This may result in heavy bleeding during a menstrual period. It may also contribute to abnormal bleeding. Heavy menstrual bleeding is usually caused by fibroids deep within the wall of the uterus (intramural) or those just under the inner lining of the uterus (submucosal). Very small fibroids in the wall of the uterus or fibroids in the outer part of the uterus usually do not cause abnormal bleeding. There are many other potential causes of heavy menstrual bleeding and a careful gynecologic history and physical examination is an important part of the evaluation of a patient with heavy bleeding.

Just because a patient has fibroids, it does not mean that the fibroids are the cause of abnormal bleeding. Other causes include endometrial hyperplasia, endometrial polyps, adenomyosis, and even uterine cancer. The likelihood of these causes is often determined based on a physical history and physical examination, but on occasion of additional tests may be needed.

If fibroids cause symptoms related to the pressure they exert on other structures, they most commonly cause a sensation of pressure or discomfort in the pelvis. This may feel like heaviness, bloating, a dull ache, or mild tenderness of the fibroids themselves. The discomfort may be greater with exercise, while bending over or during sexual intercourse. The fibroids grow, they may compress nerves that supply the pelvis and the legs, causing pain in the back, flank, or legs. Patients also report increasingly severe menstrual cramps with the growth of their fibroids.

Urinary Symptoms and Other Symptoms Pressure on the urinary system may also be caused by fibroids. Typically, this results in urinary frequency (increased frequency of urination, including the need to get up at night to urinate). Fibroids may also contribute to incontinence (urine leakage) or rarely, they may partially block the outflow of the bladder, making it difficult to empty the bladder. Occasionally, an increase in urinary flow resulting in partial blockage of the urine flow from the kidneys. On occasion, fibroids may also cause rectal pain or pressure.

Hemodynamic Iinestabilization The small intestine between red and gray contrasts with the pale pink color of the normal bowel. Patients with ulcerative colitis have a higher risk of developing colon cancer than the general population.

Many of these symptoms may be cyclic, worse in the days leading up to the menstrual period and during the period. If the fibroids get large enough, the pressure and discomfort they cause may occur at any time.

Fibroids and the Risk of a Malignant Tumor The common question is whether a large mass in the uterus, presumed to be benign fibroid, could be a malignant tumor. The answer is yes, although these tumors, called leiomyosarcomas, are very rare. They occur in about 1 in 1000 cases. Based on recent genetic studies, it does not appear that these malignant tumors result from a preexisting benign tumor. It appears to separate from any existing fibroids.

The problem is that it can be impossible to tell benign fibroid from a malignant tumor without surgery. In the imaging test, such as ultrasound or MRI, they can reliably distinguish these tumors. There is no blood test that can detect them. By history, they are often suspected when presumed fibroid grows very rapidly. However, the majority of rapidly growing fibroids are just that, benign fibroids.

Biopsy also can not reliably distinguish benign from malignant tumors of the uterus, because the sample may be taken from a relatively benign appearing portion of the mass.

Unfortunately, the reliable means of detecting malignant solid tumors of the uterus is surgery. This would either be by removal of the fibroids alone (myomectomy) or hysterectomy. Hysterectomy, with surgical removal of lymph nodes near the uterus is the primary treatment for leiomyosarcoma.

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