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Leiomyomata uteri are benign smooth muscle tumors of the uterus. They are also referred to as fibroids and uterine myomas. Myomas are the most common pelvic tumor in women, occurring in 20% of women of reproductive age. About 30% of histerectomies are performed because of myomas.
Etiology
A small number of genes have been determined to have mutated in uterine myomas. Mutations in these genes may cause uterine myomas. Myomas were discovered to be monoclonal tumors both by glucose-6-phosphate dehydrogenase isoform analysis and by analysis of polymorphisms in the androgen receptor gene. Myomas also were discovered to contain nonrandom cytogenetic abnormalities.
Anatomic Classification
Uterine myomas traditionally are classified as being sub-mucosal (beneath the endometrium), intramural (centered in the muscular wall of the uterus), or subserosal (beneath the uterine serosa). Both submucosal and subserosal tumors may become pedunculated. Submucosal myomas frequently become ulcerated and hemorrhagic.
Uterine myomas are hyperresponsive to estradiol, and the collagen genes are regulated by estrogen. Consequently, uterine myomas overproduce collagen, which contributes to their pale color and firmness.
Symptoms and Signs
Many myomas are asymptomatic. When symptoms do occur, they are most often associated with the number, size, and location of the tumors. Approximately one third of women with myomas report abnormal uterine bleeding. Most commonly the abnormal bleeding is menorrhagia.
Diagnosis
The absolute diagnosis of uterine myomata is based on surgical removal of the tissue for pathologic analysis. Definitive surgical-pathologic diagnosis of uterine myomata is not indicated in every case of suspected uterine myomata, however. In many cases, the diagnosis of uterine myomata can be presumed based solely on physical findings. Pelvic ultrasonography can be used to confirm the diagnosis and to evaluate the possibility that an adnexal mass adherent to the uterus is the cause.
Treatment
Women with asymptomatic pelvic masses believed by the clinician to be myomas are eligible for expectant management by taking serial histories and performing physical assessments at clinically indicated intervals.
Hysterectomy
Approximately one third of all hysterectomy procedures are performed to treat myomata. The severity of the symptoms, the size of the myomata, and the reproductive plans of the woman all enter into the decision to perform a hysterectomy. The ACOG-published criteria for the use of hysterectomy for the treatment.
Developing Procedures
Three new procedures that may be effective in the treatment of uterine myomata include laparoscopic myomectomy, arterial embolization of the blood supply to the myomata, and laparoscopic oophorectomy. Laparoscopic myomectomy has two major weaknesses: it can be difficult to close a deep myometrial incision by using laparoscopic techniques and it can be difficult to remove large myomata from the pelvis once they are excised from the uterus. Arterial embolization of myomata is a new procedure. In one study 16 women were treated with free-flow arterial embolization with polyvinyl sponge particles. Of the 16 women, 11 reported resolution.
Estradiol and progesterone regulate myomata size and influence uterine bleeding patterns in women with myomata. A novel approach to the treatment of menorrhagia in women with myomata is to perform an outpatient laparoscopic bilateral oophorectomy. The induction of a permanent menopausal state is Hormonal treatment of myomata has the disadvantage that once the treatment is discontinued the myomata tend to return to pretreatment size, and abnormal uterine bleeding tends to return. Hormonal treatment with a GnRH agonist analogue may be useful in helping a perimenopausal woman with myomata and menorrhagia to reach menopause without a surgical procedure. Recently, the antiprogestin mifepristone (RU 486) has been demonstrated to reduce myomata volume by approximately 50%. An advantage of antiprogestin therapy histerectomy.