Uterine fibroids
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Uterine fibroids (leiomyomata, singular leiomyoma) are the most common neoplasm in females, and may affect about 25 % of white and 50% of black women during the reproductive years. Fibroids may be removed simply by means of a hysterectomy, but much more favourably by a myomectomy or by uterine artery embolization, which preserve the uterus.
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[edit] Pathology and histology
Leiomyomas grossly appear as round, well circumscribed (but not encapsulated), solid nodules that are white, or tan whorled. The size varies, from microscopic to lesions of considerable size. Typically lesions the size of a grapefruit or bigger are felt by the patient herself through the abdominal wall. Microscopically, tumor cells resemble normal cells (elongated, spindle-shaped, with a cigar-shaped nucleus) and form bundles with different directions (whirled). These cells are uniform in size and shape, with scarce mitoses. There are three benign variants: bizarre (atypical); cellular; and mitotically active.
Leiomyomas are estrogen sensitive and have estrogen receptors. They may enlarge rapidly during pregnancy due to increased estrogen levels. As estrogen levels decline with menopause, fibroids tend to regress after menopause. Hormonal therapy is based on these facts.
More recent studies have revealed a possible role of progesterone and progestins to fibroid growth as well [1][2] and applicability of progestin agonists as part of treatment are currently being considered.[3]
[edit] Symptoms
Fibroids, particularly when small, may be entirely asymptomatic. Generally, symptoms relate to the location of the lesion and its size. Important symptoms include abnormal gynecologic hemorrhage, pain, urinary frequency or retention, and in some cases, infertility. During pregnancy they may be the cause of miscarriage, bleeding, premature labor, or interference with the position of the fetus.
[edit] Location
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 lesion may develop towards the outside of the uterus (subserosal or pedunculated), some towards the cavity (submucosal or intracavitary). Lesions affecting the cavity tend to bleed more and interfere with pregnancy. Secondary changes that may develop within fibroids are hemorrhage, necrosis, calcification, and cystic changes. Less frequently, leiomyomas may occur at the lower uterine segment, cervix, or uterine ligaments.
[edit] Diagnosis
Diagnosis is usually accomplished by bimanual examination, better yet by gynecologic ultrasonography. Sonography will depict the fibroids as focal masses with a heterogeneous texture, which usually cause shadowing of the ultrasound beam. In cases where a more precise assay of the fibroid burden of the uterus is needed, also magnetic resonance imaging (MRI) can be used to generate a depiction of the size and location of the fibroids within the uterus. While no imaging modality can clearly distinguish between the benign uterine leiomyoma and the malignant uterine leiomyosarcoma, the rarity of the latter and the prevalence of the former make it, for practical purposes, a non-issue unless evidence of local invasion is present, though more recent studies have improved diagnostic capabilities using MRI [4]. For this reason, biopsy is rarely performed and if performed, is rarely diagnostic.
[edit] Treatment
The presence of a fibroid does not mean that it needs to be treated; many lesions are followed expectantly depending upon the symptomatology and presence of related conditions, such as anemia. Treatment of uterine fibroids that cause problems can be accomplished by:
- Surgery: Hysterectomy or myomectomy can be performed. Based on the size and location of the lesion, different approaches can be considered: laparotomy, laparoscopy, or hysteroscopy.
- Uterine artery embolization (UAE): Using interventional radiology techniques, the Interventional physician occludes both uterine arteries, thus reducing blood supply to the fibroid(s).
- Medical therapy: First line treatment may involve oral contraceptive pills, either combination pills or progestin-only, in an effort to manage symptoms. If unsuccessful, further medical therapy involves the use of medication to reduce estrogens in an attempt to create a medical menopause-like situation. Gonadotropin-releasing hormone analogs are used for this. GNRH analogs, however, are short term treatments only. Selective progesterone receptor modulators, such as Progenta, are under investigation as therapeutic agents, as of 2005.
- HIFU (High intensity focused ultrasound), also called Magnetic Resonance guided Focused Ultrasound, is a non-invasive intervention (requiring no incision) that uses high intensity focused ultrasound waves to ablate (destroy) tissue in combination with Magnetic Resonance Imaging (MRI), which guides and monitors the treatment. This technique is relatively new; it was approved by the FDA in 2005.
[edit] Malignancy
Very few lesions are or become malignant. Signs that a fibroid may be malignant are rapid growth or growth after menopause. Such lesions are typically a leiomyosarcoma on histology.
