A uterine fibroid is a (leiomyoma) is a benign (non-cancerous) tumour that originates from the smooth muscle layer (myometrium) of the uterus. Fibroids are often multiple. The malignant version of a fibroid is extremely uncommon and termed a leiomyosarcoma. Other common names are uterine leiomyom, myoma, fibromyoma, fibroleiomyoma.
Fibroids are the most common benign tumors in females and typically found during the middle and later reproductive years. While most fibroids are asymptomatic, they can grow and cause heavy and painful menstruation, painful sexual intercourse, and urinary frequency and urgency. Some fibroids may interfere with pregnancy although this appears to be very rare.
Growth and location are the main factors that determine if a fibroid leads to symptoms and problems. A small fibroid can be symptomatic if located within the uterine cavity while a large fibroid on the outside of the uterus may go unnoticed. Different locations are classified as follows:
- Intramural fibroids are located within the wall of the uterus and are the most common type; unless large, they may be asymptomatic. Intramural fibroids begin as small nodules in the muscular wall of the uterus. With time, intramural fibroids may expand inwards, causing distortion and elongation of the uterine cavity.
- Subserosal fibroids are located underneath the mucosal (peritoneal) surface of the uterus and can become very large. They can also grow out in a papillary manner to become pedunculated fibroids. These pedunculated growths can actually detach from the uterus to become a parasitic leiomyoma.
- Submucosal fibroids are located in the muscle beneath the endometrium of the uterus and distort the uterine cavity; even small lesion in this location may lead to bleeding and infertility. A pedunculated lesion within the cavity is termed an intracavitary fibroid and can be passed through the cervix.
- Cervical fibroids are located in the wall of the cervix (neck of the uterus). Rarely fibroids are found in the supporting structures (round ligament, broad ligament, or uterosacral ligament) of the uterus that also contain smooth muscle tissue.
Fibroids may be single or multiple. Most fibroids start in an intramural location, that is the layer of the muscle of the uterus. With further growth, some lesions may develop towards the outside of the uterus or towards the internal cavity. Secondary changes that may develop within fibroids are hemorrhage, necrosis, calcification, and cystic changes.
Fibroids, particularly when small, may be entirely asymptomatic. Symptoms depend on the location of the lesion and its size. Important symptoms include abnormal hemorrhage, heavy or painful periods, abdominal discomfort or bloating, painful defecation, back ache, urinary frequency or retention, and in some cases, infertility. There may also be pain during intercourse, depending on the location of the fibroid. During pregnancy they may be the cause of miscarriage, bleeding.
Fibroids are almost always benign (not cancerous). Rarely (less than one in 1,000) a cancerous fibroid will occur. This is called leiomyosarcoma.
Infertility, while fibroids are common, they are accounting for about 3% of reasons why a woman may not have a child. In such cases a fibroid is located in a submucosal position and it is thought that this location may interfere with the function of the lining and the ability of the embryo to implant. Also larger fibroids may distort or block the fallopian tubes.
Fibroids that lead to heavy vaginal bleeding lead to iron deficiency anaemia . Due to pressure effects gastrointestinal problems are possible such as constipation and bloatedness. Compression of the ureter may lead to hydronephrosis (enlargement of the kidneys). Fibroids may also present alongside endometriosis, which itself may cause infertility. In very rare cases, malignant (cancerous) growths, leiomyosarcoma, of the myometrium can develop.
Combined abdominal and vaginal examination: typically can identify the presence of larger fibroids,
- Ultrasound: is the standard tool to evaluate the uterus for fibroids.
- MRI: magnetic resonance imaging can be used to define the depiction of the size and location of the fibroids within the uterus.
Most fibroids are small and do not require treatment unless they are causing symptoms. After menopause small fibroids shrink and it is unusual for fibroids to cause problems.
Symptomatic uterine fibroids can be treated by:
A number of medications are in use to control symptoms caused by fibroids.
- NSAIDs (Ibuprofen, Voltaren etc) can be used to reduce painful menses.
- Oral contraceptive pills: are prescribed to reduce uterine bleeding and cramps.
- Iron supplementation: for treatment ofanaemia.
- Levonorgestrel (Mirena) intrauterine devices - are highly effective in limiting menstrual blood flow. Side effects are typically very moderate because the levonorgestrel (a progestin) is released in low concentration locally. There is now substantial evidence that Levongestrel-IUDs provide good symptomatic relief for women with fibroids. While most Levongestrel-IUD studies concentrated on treatment of women without fibroids a few reported very good results specifically for women with fibroids including a substantial regression of fibroids.
- Danazol - is an effective treatment to shrink fibroids and control symptoms. Its use is limited by unpleasant side effects. Mechanism of action is thought to be antiestrogenic effects. Recent experience indicates that safety and side effect profile can be improved by more cautious dosing.
- Dostinex - in a moderate and well tolerated doses has been shown in 2 studies to shrink fibroids effectively. Mechanism of action is completely unclear.
- Gonadotropin releasing hormone analogs- cause temporary regression of fibroids by decreasing estrogen levels. Because of the limitations and side effects of this medication it is rarely recommended other than for preoperative use to shrink the size of the fibroids and uterus before surgery. Its is typically used for a maximum of 6 months or shorter because after longer use they could cause osteoporosis and other typically postmenopausal complications. The main side effects are transient postmenopausal symptoms.
In many cases the fibroids will regrow after cessation of treatment, however significant benefits may persists for much longer time in some cases. Several variations are possible, such as GnRH agonists with add-back regimens intended to decrease the adverse effects of estrogen deficiency. Several add-back regimes are possible, tibolone, raloxifene, progestogens alone, estrogen alone, and combined estrogens and progestogens.
Submucosal fibroid in hysteroscopy.
Treatment of an intramural fibroid by laparoscopic surgery
After treatment of an intramural fibroid by laparoscopic surgery.
Myomectomy is a surgery to remove one or more fibroids. It is usually recommended when more conservative treatment options fail for women who want fertility preserving surgery or who express desire to retain the uterus. This surgery is fertility preserving although in some circumstances subsequent pregnancies can be difficult or impossible.
There are three techniques types of myomectomy:
- In a hysteroscopic myomectomy, the fibroid is removed by the use of a resectoscope, an endoscopic instrument inserted through the vagina and cervix that can use high-frequency electrical energy to cut tissue. Hysteroscopic myomectomies can be done as an outpatient procedure, with either local or general anesthesia used. Hysteroscopic myomectomy is most often recommended for submucosal fibroids. A French study collected results from 235 patients suffering from submucous myomas who were treated with hysteroscopic myomectomies; in none of these cases was the fibroid greater than 5 cm.
- A laparoscopic myomectomy requires a small incision near the navel. The physician then inserts a laparoscope into the uterus and uses surgical instruments to remove the fibroids. Studies have suggested that laparoscopic myomectomy leads to lower morbidity rates and faster recovery than does laparotomic myomectomy. As with hysteroscopic myomectomy, laparoscopic myomectomy is not generally used on very large fibroids. A study of laparoscopic myomectomies conducted between January 1990 and October 1998 examined 106 cases of laparoscopic myomectomy, in which the fibroids were intramural or subserous and ranged in size from 3 to 10 cm.
- A laparotomic myomectomy (also known as an open or abdominal myomectomy) is the most invasive surgical procedure to remove fibroids. The physician makes an incision in the abdominal wall and removes the fibroid from the uterus. A particularly extensive laparotomic procedure may necessitate that any future births be conducted by Caesarean section. Recovery time from a laparatomic procedure is generally expected to be four to six weeks.
Hysterectomy is the classical method of treating fibroids. Although it is now recommended only as last option, fibroids are still the leading cause of hysterectomies in the US.
Endometrial ablation can be used if the fibroids are only within the uterus and not intramural and relatively small. High failure and recurrence rates are expected in the presence of larger or intramural fibroids.