Uterine Fibroids

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UTERINE FIBROIDS (UTERINE MYOMAS)

Introduction
The uterus is composed of a thick layer of smooth muscle (myometrium) that surrounds the lining (the endometrium) into which the embryo implants. Approximately 10-20% of all reproductive age women will develop benign growths of the myometrium, referred to as fibroid tumors (myomas). Estrogen stimulates their growth and these tumors are rarely malignant (cancerous). They can be located in the wall of the uterus (intramural), on the outside of the uterus (subserosal), within the uterine cavity (submucosal), on a thin stalk (pedunculated) or a combination of the above.

Presentation, Symptoms and Signs Associated with Uterine Fibroids


Fibroids, even large ones, can be present without any symptoms at all. However, they can also cause a variety of symptoms depending on their size, location and the absence or presence of complications such as torsion (twisting) or degeneration (fibroid grows to an extent that it starts running out of its blood supply). The most common symptoms are heavy cyclical menstrual bleeding (menorrhagia) accompanied by menstrual pain (dysmenorrhea). Sometimes, especially when a fibroid protrudes into the uterine cavity, it can cause erosion of the endometrial lining and produce irregular or continuous bleeding (meno-metrorrhagia). Other possible symptoms include pain with deep penetration during intercourse (dyspareunia), bladder irritability, rectal pressure, constipation and painful bowel movements (dyschezia).

Effect of Fibroids on Reproduction

For the most part, only those fibroids that impinge upon the endometrial cavity (submucosal) or multiple fibroids in the muscle layer without a direct impact may adversely affect fertility. Exceptions include large intramural fibroids that block the openings of the fallopian tubes into the uterus, and where multiple fibroids cause abnormal uterine contraction patterns. Surgery to treat fibroids can also affect fertility in several ways. If the endometrial cavity is entered during the surgery, there is a possibility of post operative adhesion formation within the uterine cavity. This should always be checked by a hysteroscopy or fluid ultrasound (hydrosonography) prior to beginning fertility treatment. Because myomectomy can be bloody, there is a high likelihood of abdominal adhesion formation, which could encase the ovaries, preventing the release of the eggs or blocking the ends of the fallopian tubes. For this reason it is important that experienced surgeons or reproductive endocrinologists, who are familiar with surgical techniques to limit blood loss and prevent adhesion formation, perform myomectomy.

In some cases multiple uterine fibroids may also deprive the endometrium of blood flow, that the delivery of estrogen to the uterine lining (endometrium) is curtailed to the point that it cannot thicken enough to support a pregnancy. This can result in early 1st trimester miscarriages (prior to the 13th week of pregnancy). Large or multiple fibroids, by curtailing the ability of the uterus to stretch in order to accommodate the spatial needs of a rapidly growing pregnancy, may precipitate recurrent 2nd trimester miscarriages (beyond the 13th week) and/or trigger the onset of premature labor.

Diagnosis

Sizable fibroids are usually easily identified by simple vaginal–pelvic bimanual examination. However, even the smallest fibroid can be identified by transvaginal ultrasound. Sometimes it is difficult to tell if a fibroid is impinging on the endometrial cavity. In such cases, a hysteroscopy (where a telescope-like instrument, inserted via the vagina into the uterine cavity) or a hydrosonogram (where salt water distends the uterine cavity, allowing for examination of its contour and inner configuration) can help distinguish between intramural and submucosal fibroids. Magnetic Resonance Imaging (MRI) can be used to distinguish between fibroid tumors and a related condition called adenomyosis, in which diffuse or localized foci of endometrium is found within the myometrium. Given the often-diffuse nature of adenomyosis, it is difficult to remove surgically. This contrasts with fibroid tumors, which are well defined and are usually easily removed.

Surgical Treatment of Fibroid Tumors

The treatment of fibroid tumors in infertility patients is surgical removal (myomectomy). Small, asymptomatic fibroids that do not impinge upon the endometrial cavity will usually not require treatment other than observation. Large fibroids and submucosal fibroids should be removed prior to starting fertility treatments such as in vitro fertilization (IVF) in order to decrease the chance of implantation failure, miscarriage, pregnancy complications and premature labor. Intramural and subserosal fibroids are readily removable by laparoscopic resection or via an abdominal incision (laparotomy). The former allows for a more rapid convalescence and is ideal for the removal of small and accessible superficial fibroid tumors, while the latter approach is preferred for treating larger, multiple and less accessible fibroids.

Regardless of whether the laparoscopic or abdominal approach is employed, adequate closure of the uterine wall is essential in order to reduce the subsequent risk of uterine rupture during pregnancy or labor. This is one of the main arguments used against the use of laparoscopic removal of large, multiple or remotely situated fibroids. While laparoscopic myomectomy requires fewer days for post-operative convalescence, abdominal myomectomy usually requires 4-6 weeks of recovery time. When myomectomy necessitates or results in the uterine cavity being entered (purposefully or inadvertently), it should be followed up with a hysteroscopy to rule out scar tissue formation, which occurs frequently in the presence of submucosal fibroids.

Uterine polyps (and in some cases, also submucosal fibroids), can often be removed hysteroscopically (through the vagina). This eliminates the need for abdominal surgery and greatly reduces the recovery time. Hysteroscopic surgery is only useful if the majority of the fibroid protrudes into the endometrial cavity, ensuring that the tumor defect will not be too large. After hysteroscopic surgery, cyclical hormonal therapy can be prescribed based on the extent of the surgery and endometrial involvement to assist regeneration of the endometrial lining. A hysteroscopy should be performed afterwards to rule out scar tissue formation and to confirm a normal endometrial cavity.

Medical Treatment for Fibroid Tumors

The growth of fibroid tumors is estrogen-dependent. Thus, when a woman enters the menopause and stops producing female hormones, fibroids tend to shrink in size. Conditions that mimic menopause can also reduce the size of fibroid tumors. The most common of these is treatment with a medication such as leuprolide acetate (Lupron), which shut off the communication of the brain with the ovaries, preventing hormone production. However, this type of medication can only be taken for a limited period (usually 6 months) and once the medication is stopped the fibroids will usually regain their original size within a few months. The medication is therefore only a “temporary fix”; used mostly to decrease the size of large fibroids in order to make their ultimate surgical removal easier or to help a woman bridge the gap until spontaneous menopause sets in. For the majority of women there is no major benefit from Lupron therapy prior to surgery.

Embolization of Fibroid Tumors

Embolization is a procedure in which small particles are injected into the arteries of the fibroid under radiological guidance to shut off the blood supply to the fibroids, in the hope that they will shrink. Embolization is relatively new to the field of gynecology and may have potential adverse effects on future fertility. Currently, embolization is not a recommended therapy for fibroids in women who still wish to conceive. It may be considered as an option for the treatment of fibroids in women who do not desire future fertility or have completed child bearing.

Malignant Change in Fibroids

Fibroids rarely undergo malignant change. The reported incidence is less than 1 : 2000. Fibroids usually grow very slowly (over a number of years). However, when growth occurs rapidly over a month or two, especially in older women who have large fibroids, it should raise the suspicion of this very rare but extremely serious complication.