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Uterine fibroids (singular Uterine Fibroma) (leiomyomata, singular leiomyoma) are benign tumors which grow from the muscle layers of the uterus. They are the most common neoplasm in females, and may affect about 25% of white and 50% of black women during the reproductive years. Uterine fibroids often do not require treatment, but when they are problematic, they may be treated surgically or with medication — possible interventions include a hysterectomy, hormonal therapy, a myomectomy, or uterine artery embolization. Uterine fibroids shrink dramatically in size after a woman passes through menopause.
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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 arise from the smooth muscle (myometrium) and of the components of the Extracellular Matrix (ECM). 
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, and applicability of progestin agonists as part of treatment are currently being considered.
The symptoms depend on the size, location, number, and the pathological findings. 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.
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 (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.
Diagnosis is usually accomplished by bimanual examination, better yet by gynecologic ultrasonography, commonly known as "ultrasound." 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 definite the 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, because of the rarity of the latter and the prevalence of the former until that time, for practical purposes, there is no result unless it is evidence of local invasion is present, though more recent studies have improved diagnostic capabilities using MRI. For this reason, biopsy is rarely performed and if performed, is rarely diagnostic.
The presence of a fibroid does not mean that it needs to be treated; it is expectantly depending on the symptomatology and presence of related conditions, such as anemia. The presence of uterine fibroids can cause problems which can be solved by:
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. There is no consensus among pathologists regarding the transformation of Leiomyoma into a sarcoma. Most pathologists believe that a Leiomyosarcoma is a de novo disease.
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Uterine_fibroids". A list of authors is available in Wikipedia.|