Clinical Fibroids

INTRODUCTION — Uterine leiomyomas (fibroids or myomas) are [K1] the most common pelvic tumor in women [1-3]. They are benign monoclonal tumors arising from the smooth muscle cells of the myometrium. They arise in reproductive age women and typically present with symptoms of heavy or prolonged menstrual bleeding or pelvic pain/pressure. Uterine fibroids may also have reproductive effects (eg, infertility, adverse pregnancy outcomes).
The epidemiology, clinical manifestations, diagnosis, and natural history of uterine leiomyomas are reviewed here. Treatment of uterine leiomyomas, leiomyoma histology and pathogenesis, differentiating leiomyomas from uterine sarcomas, and leiomyoma variants are discussed separately. (See "Overview of treatment of uterine leiomyomas (fibroids)" and "Histology and pathogenesis of uterine leiomyomas (fibroids)" and "Differentiating uterine leiomyomas (fibroids) from uterine sarcomas" and "Variants of uterine leiomyomas (fibroids)".)
TERMINOLOGY AND LOCATION — Fibroids are often described according to their location in the uterus, although many fibroids have more than one location designation (figure 1 and picture 1A-B). An International Federation of Gynecology and Obstetrics (FIGO) staging scheme for fibroid location has been proposed (figure 2) [4].
●Intramural myomas (FIGO type 3,4,5) – These leiomyomas develop from within the uterine wall. They may enlarge sufficiently to distort the uterine cavity or serosal surface. Some fibroids can be transmural and extend from the serosal to the mucosal surface.
●Submucosal myomas (FIGO type 0,1,2) – These leiomyomas derive from myometrial cells just below the endometrium. These neoplasms protrude into the uterine cavity. The extent of this protrusion is described by the FIGO/European Society of Hysteroscopy classification system and is clinically relevant for predicting outcomes of hysteroscopic myomectomy [5]. A type 0 fibroid is completely intracavitary, type I has less than 50 percent of its volume in the uterine wall, whereas a type II has 50 percent or more of its volume in the uterine wall (figure 3). Types 0 and I are hysteroscopically resectable, although significant hysteroscopic expertise may be needed to resect type I masses. (See "Hysteroscopic myomectomy", section on 'Myometrial penetration'.)
●Subserosal myomas (FIGO type 6,7) – These leiomyomas originate from the myometrium at the serosal surface of the uterus. They can have a broad or pedunculated base (image 1) and may be intraligamentary (ie, extending between the folds of the broad ligament).
●Cervical myomas (FIGO type 8) – These leiomyomas are located in the cervix, rather than the uterine corpus.
PREVALENCE — Uterine leiomyomas are the most common pelvic tumor in women, as noted above [1-3]. A hysterectomy study found myomas in 77 percent of uterine specimens [6].
The epidemiology of leiomyomas parallels the ontogeny and life cycle changes of the reproductive hormones estrogen and progesterone. Although the growth of fibroids is responsive to gonadal steroids, these hormones are not necessarily responsible for the genesis of the tumors. (See "Histology and pathogenesis of uterine leiomyomas (fibroids)", section on 'Steroid hormones'.)
Leiomyomas have not been described in prepubertal girls, but they are occasionally noted in adolescents. Myomas are clinically apparent in approximately 12 to 25 percent of reproductive age women and noted on pathological examination in approximately 80 percent of surgically excised uteri [2,6,7]. In hysterectomy specimens sectioned at 2-mm intervals, premenopausal women had an average 7.6 fibroids [6]. Most, but not all, women have shrinkage of leiomyomas at menopause.
RISK FACTORS[K2]
Race — The incidence rates of fibroids are typically found to be two- to three-fold greater in black women than in white women [1,8,9]. In one study, the estimated cumulative incidence of fibroids of any size, including very small tumors, by age 50 was >80 percent for black women and almost 70 percent for white women [1]. Clinically relevant fibroids (uterine enlargement greater than or equal to nine weeks size, fibroid greater than or equal to 4 cm, or submucosal fibroid) are detectable by transvaginal sonography in approximately 50 percent of black women in the menopausal transition and 35 percent of white women in the menopausal transition [1].
The etiology of the increased incidence of leiomyomas in black women is unknown. It cannot be explained by known factors that vary by race [9]. There have been studies that correlated the presence of fibroids in African American women with polycystic ovarian syndrome [10].
The natural history of leiomyomas also differs by race. Most white women with symptomatic fibroids are in their 30s or 40s; however, black women develop symptoms on average four to six years younger and may even present with disease in their 20s [11,12]. The prevalence of fibroids in women 30 years old and younger appears to be significantly higher with about a quarter of black women having fibroids compared to 7 percent of white women [13]. In addition, it appears that fibroids grow at a slower rate after age 35 in white women, but not in black women [14]. Compared with white women, black women experience more severe disease based on their symptoms and have more extensive disease at the time of hysterectomy [11,12].
The rate of hysterectomy for fibroids is greater among black women than among white women (38 versus 16 per 10,000 women) [15]. Also, among women undergoing hysterectomy, black women appear to have surgery at a younger age, have larger uteri, and more severe anemia [11,12]. There is also increased risk of myomectomy and hospitalization for fibroids for black women [16]. Finally, there is increasing evidence of increases in symptomatology for black women with fibroids apart from those seeking surgical therapy, increased impairment of quality of life, different concerns regarding fibroids and the consequences of fibroid therapies and less satisfaction with the information they receive about fibroids [17].
Data are mixed regarding whether Latina women have an increased risk of uterine myomas compared with non-Latina white women [9,15]. The risk was 1.3-fold in a prospective study of 133,000 women [15]. Some of this variation may be accounted for whether black Latina women are included in the analysis.
Menstrual history and parity — Early menarche (<10 years old) is associated with an increased risk of developing fibroids. This may largely account for the early onset of disease in black women in whom menarche is generally earlier than in white women [11,18-21]. Additionally, prenatal exposure to diethylstilbestrol is associated with an increased risk of fibroids, supporting the role of early hormonal exposure in pathogenesis [22]. In white women, a specific polymorphism in the transcription factor HMGA2 appears to be linked to both uterine leiomyomas and shorter adult height, suggesting that early menarche may be a key influence [19].
Parity (having one or more pregnancies extending beyond 20 weeks) decreases the chance of fibroid formation [23-25]. It has been hypothesized that the postpartum remodeling of the uterus may have the effect of clearing smaller fibroids [26]. Recent studies supported this hypothesis with the finding that over a third of women with a single fibroid identified during pregnancy had none on postpartum ultrasound, and almost 80 percent of fibroids were smaller following pregnancy [27]. In some cohorts, early age at first birth decreases risk and a longer interval since last birth increases risk [18].
Hormonal contraception — Use of low dose oral contraceptives (OCs) does not cause fibroids to grow, therefore administration of these drugs is not contraindicated in women with fibroids [18,23,28-30]. One possible exception was reported by the Nurses' Health Study, which suggested OC use increased the risk of leiomyomas in women with early exposure to OCs (13 and 16 years old) [25].
Long acting progestin-only contraceptives (eg, depot medroxyprogesterone) protect against development of leiomyomas [18,30,31]. However, recent studies of postpartum fibroid regression suggest that these agents inhibit fibroid regression when used in the postpartum period [32].
Ovulation induction agents — There are isolated reports of leiomyoma enlargement in women treated with clomiphene [33,34]. However, both cases reported occurred in the era before clinical use of ultrasound and the only presurgical assessment of the size of fibroids was pelvic examination and culdoscopy. Given the frequency of ultrasound monitoring in conjunction with current fertility treatments and the dearth of case reports, the association of fibroid growth with agents for ovulation induction is unlikely [35].
Obesity — Most studies show a relationship between fibroids and increasing body mass index; however, a relationship with increased body mass index, weight gain as an adult, or body fat varies between studies. The relationship is complex and is likely modified by other factors, such as parity, and may be more related to change in body habitus as an adult [28,36-40].
Diet, caffeine, and alcohol use — Significant consumption of beef and other reds meats (1.7-fold) or ham (1.3-fold) is associated with an increased relative risk of fibroids and consumption of green vegetables (0.5-fold) and fruit (especially citrus fruit) with a decreased risk [41,42]. One report suggested that consumption of dairy products, but not soy products, is inversely related to fibroid risk in black women [43]. Dietary consumption of carotenoids is not associated with a change in risk for uterine leiomyoma [44]. Recent data suggest that consumption of dairy products is inversely associated with leiomyoma risk in black women [43]. There was no confounding effect of soy consumption, which is often a substitute for dairy products in lactose intolerant women [43]. Dietary vitamin A from animal sources may also be associated with decreased fibroid risk [42]. Increases in dietary glycemic index or load are associated with a weak increase in fibroid risk in some women [45]. There is increasing evidence that vitamin D deficiency or insufficiency is linked to fibroid risk [46,47]. This is especially interesting because it is a biologically-plausible explanation for the increased fibroid risk in black women that lends itself to prevention trials.
Consumption of alcohol, especially beer, appears to increase the risk of developing fibroids [48].
Caffeine consumption is not a risk factor.
Smoking — Smoking decreases the risk of having fibroids through an unknown mechanism. Smoking does not appear to affect estrogen metabolism [23,49].
Heredity — Studies imply a familial predisposition to leiomyomas in some women. There is also increasing evidence of specific susceptibility genes for fibroids [50-52]. (See "Histology and pathogenesis of uterine leiomyomas (fibroids)", section on 'Genetics'.)
Other factors — Hypertension is associated with an increased leiomyoma risk. The risk is related to increased duration or severity of hypertension [53]. Environmental phthalate exposure appears to be linked to an increased risk of fibroids, especially in women with concomitant endometriosis [54]. There appears to be a link between a history of physical or sexual abuse and fibroids, especially in black women [55-57]. A study found a correlation of the presence of fibroids in African American women with self-reported experience of racism [10].
The link between uterine infection appears to be associated with an increased risk of leiomyomas, yet factors associated with cervical neoplasia are associated with a decreased risk [53,58]. Additional study is indicated regarding infectious agents and fibroid risk.
CLINICAL MANIFESTATIONS — Symptoms attributable to uterine myomas can generally be classified into three distinct categories:
●Heavy or prolonged menstrual bleeding
●Pelvic pressure and pain
●Reproductive dysfunction
Although the majority of myomas are small and asymptomatic, many women with fibroids have significant problems that interfere with some aspect of their lives and warrant therapy [17]. These symptoms are related to the number, size, and location of the neoplasms. Myomas can occur as single or multiple tumors and range in size from microscopic to tens of centimeters. The size of the myomatous uterus is described in menstrual weeks, as with the gravid uterus. As an example, a 20-week size myomatous uterus is not unusual, and is often associated with heavy menses, increasing abdominal girth, and a sense of abdominal fullness similar to pregnancy.
Heavy or prolonged menstrual bleeding — Heavy and/or prolonged menses is the typical bleeding pattern with myomas and the most common fibroid symptom [59]. Intermenstrual bleeding and postmenopausal bleeding are NOT characteristic of myomas and should be investigated to exclude endometrial pathology. Heavy uterine bleeding may be responsible for associated problems, such as iron deficiency anemia, social embarrassment, and lost productivity in the work force. (See "Evaluation of the endometrium for malignant or premalignant disease".)
The presence and degree of uterine bleeding are determined, in large part, by the location of the fibroid; size is of secondary importance. (See 'Terminology and location' above.) Submucosal myomas that protrude into the uterine cavity (eg, types 0 and I) (figure 3) are most frequently related to significant menorrhagia [2,5,60]. As an example, a retrospective study that included 912 women with leiomyomas found that those with submucosal myomas were significantly more likely to be anemic than women with myomas in other locations (34 versus 25 percent) [61]. However, women with intramural myomas also commonly experience heavy or prolonged menstrual bleeding. The mechanism(s) of profuse menses are unclear, but may include both microscopic and macroscopic abnormalities of the uterine vasculature, impaired endometrial hemostasis, or molecular dysregulation of angiogenic factors [62].
Pelvic pressure and pain
Bulk-related symptoms — The myomatous uterus is irregularly shaped, in contrast to the pregnant uterus, and can cause specific symptoms due to pressure from myomas at particular locations. As examples, urinary frequency, difficulty emptying the bladder, and, rarely, urinary obstruction can all occur with fibroids; symptoms sometimes arise when an anterior fibroid presses directly on the bladder or a posterior fibroid pushes the entire uterus forward. Silent, ureteric compression leading to renal hydronephrosis is rare [63]. Fibroids that place pressure on the rectum can result in constipation. Back pain may, on occasion, be related to the presence of myomas, but other possible causes should be considered. Very large uteri may compress the vena cava and lead to increase in thromboembolic risk [64-66]. At least one study suggests the risk of venous thromboembolism is likely to be the presenting complaint associated with an enlarged uterus rather than a postsurgical complication [64].
Dysmenorrhea — Dysmenorrhea is also reported by many women with fibroids. This pain in many women appears to be correlated with heavy menstrual flow and/or passage of clots.
Dyspareunia — It is controversial whether women with fibroids in any location are more likely to experience dyspareunia than women without fibroids [67,68]. However, among women with fibroids, anterior or fundal fibroids are the most likely to be associated with deep dyspareunia. Number and size of fibroids do not appear to influence the incidence or intensity of dyspareunia.
Leiomyoma degeneration or torsion — Infrequently, fibroids cause acute pain from degeneration (eg, carneous or red degeneration) or torsion of a pedunculated tumor. Pain may be associated with a low grade fever, uterine tenderness on palpation, elevated white blood cell count, or peritoneal signs. The discomfort resulting from degenerating fibroids is self-limited, lasting from days to a few weeks, and usually responds to nonsteroidal antiinflammatory drugs. Ultrasound is used for the primary diagnosis of fibroids. Degeneration can be suggested when pain is present when scanning directly over the fibroid. In cases where the etiology of pain is unclear, pelvic magnetic resonance imaging with gadolinium can be useful to make the diagnosis of degeneration since degenerating fibroids do not have enhancement following contrast administration [69]. If acute pain is the sole indication for surgery, other disease processes, such as endometriosis and renal colic, or rare diagnoses such as pelvic tuberculosis, should be carefully excluded [70,71]. (See "Pathogenesis, clinical features, and diagnosis of endometriosis".)
Effects on reproduction — Leiomyomas that distort the uterine cavity (submucosal or intramural with an intracavitary component) result in difficulty conceiving a pregnancy and an increased risk of miscarriage [72]. In addition, leiomyomas have been associated with adverse pregnancy outcomes (eg, placental abruption, fetal growth restriction, malpresentation, and preterm labor and birth). These issues are discussed in detail separately. (See "Reproductive issues in women with uterine leiomyomas (fibroids)" and "Pregnancy in women with uterine leiomyomas (fibroids)".)
Other — Infrequently, a leiomyoma will present with transcervical prolapse, resulting in ulceration or infection.
Rare symptoms of fibroid tumors that appear to be related to ectopic hormone production include:
●Polycythemia from autonomous production of erythropoietin [73]
●Hypercalcemia from autonomous production of PTHrP [74]
●Hyperprolactinemia [75]
DIAGNOSIS — The presumptive diagnosis of uterine myomas is usually based upon the finding of an enlarged, mobile uterus with an irregular contour on bimanual pelvic examination. Typically, an ultrasound is used to confirm the diagnosis and exclude the possibility of another type of uterine mass or an adnexal mass.
Pelvic examination — A thorough pelvic examination should be performed. On bimanual pelvic examination, an enlarged, mobile uterus with an irregular contour is consistent with a leiomyomatous uterus. The size, contour, and mobility of the uterus should be noted, along with any other findings (eg, adnexal mass, cervical mass). These findings are helpful to follow changes in the uterus over time and to aid surgical planning (eg, plan transverse or vertical incision).
Infrequently, on speculum exam, a prolapsed submucosal fibroid may be visible at the external cervical os. These should be removed and are distinguished from a large endocervical or endometrial polyp by the firm consistency of the tissue and by pathologic evaluation. (See "Prolapsed uterine leiomyoma (fibroid)".)
Imaging — When a myoma is suspected based upon symptoms or pelvic examination findings, imaging or hysteroscopy are useful to exclude the possibility of another type of uterine mass or an adnexal mass. (See 'Differential diagnosis' below.) Computed tomography has little clinical utility in delineating the position of fibroids relative to the endometrium or myometrium [76].
Ultrasound — Transvaginal ultrasound has high sensitivity (95 to 100 percent) for detecting myomas in uteri less than 10 weeks' size. Localization of fibroids in larger uteri or when there are many tumors is limited [77]. This is the most widely used modality due to its availability and cost-effectiveness.
Saline infusion sonography (sonohysterography) improves characterization of the extent of protrusion into the endometrial cavity by submucous myomas and allows identification of some intracavitary lesions not seen on routine ultrasonography (image 2). (See "Saline infusion sonohysterography".)
Calcification in a fibroid generally implies that it has necrosed. These calcifications can be seen on plain film as “popcorn” calcifications in the pelvis. On ultrasound, the calcifications can appear as clumps or rim-like calcifications within a mass (image 3). At times only the calcification is seen, and not the soft tissue component. In general, if compared with a sonogram pre-necrosis, the fibroid size will be smaller once it calcifies.
Diagnostic hysteroscopy — Diagnostic hysteroscopy can be performed in the office with a flexible or rigid hysteroscope. When the entire fibroid is visualized arising from a pedicle, or has a broad base, the lesion is hysteroscopically classified as intracavitary. However, when the fibroid abuts the endometrium or protrudes into the myometrium, the depth of penetration cannot be ascertained hysteroscopically. Additionally, hysteroscopy less accurately predicts the size of the myoma compared with ultrasound and sonohysterography [78].
Magnetic resonance imaging — Magnetic resonance imaging is the best modality for visualizing the size and location of all uterine myomas and can distinguish among leiomyomas, adenomyosis, and adenomyomas. Due to the expense of this modality, its use is best reserved for surgical planning for complicated procedures. It may also be useful in differentiating leiomyomas from leiomyosarcomas, and before uterine artery embolization since imaging patterns predict uterine artery embolization outcome [79,80].
Hysterosalpingography — A hysterosalpingogram (HSG) is a good technique for defining the contour of the endometrial cavity. It has poor ability to visualize the rest of the myometrium and can falsely identify an intramural fibroid impinging on the uterine cavity as a submucosal fibroid. It is typically used to visualize myomas only when a HSG is needed to evaluate tubal patency in women with infertility. (See "Hysterosalpingography".)
DIFFERENTIAL DIAGNOSIS — A normal nonpregnant uterus weighs approximately 70 g. The differential diagnosis of an enlarged uterus includes both benign and malignant conditions:
●Leiomyoma
●Uterine adenomyosis or adenomyoma
●Leiomyoma variant
●Adenomatoid tumors
●Pregnancy
●Hematometra
●Uterine sarcoma
●Uterine carcinosarcoma
●Endometrial carcinoma
●Metastatic disease (typically from another reproductive tract primary)
The following sections will review aspects of these conditions that are relevant to distinguishing them from leiomyomas and uterine sarcoma.
Benign conditions
Adenomyosis or adenomyoma — Among the etiologies of a uterine mass, adenomyoma is the most likely to resemble a leiomyoma on pelvic imaging and intraoperative examination. Diffuse adenomyosis can also cause uterine enlargement without the presence of a discrete mass.
Similar to leiomyomas or uterine sarcoma, adenomyomas typically present with abnormal uterine bleeding. One characteristic that may distinguish adenomyomas from leiomyomas or sarcoma is the presence of dysmenorrhea as a prominent symptom. However, dysmenorrhea is a common gynecologic symptom and may be present in some women with leiomyomas. In addition, adenomyosis and fibroids often occur in the same woman, making differentiation more difficult. Again, pain symptoms and symptoms that appear significant despite modest uterine enlargement appear to indicate adenomyosis may coexist with leiomyomas [81,82].
Adenomyomas are generally more difficult to excise than leiomyomas. Leiomyomas are typically separated from the adjacent myometrium by a pseudocapsule. With adenomyomas, there is typically no tissue plane between the adenomyoma and the myometrium. Uterine sarcomas are also likely to be difficult to excise.
The diagnosis of uterine adenomyosis is discussed separately. (See "Uterine adenomyosis", section on 'Diagnosis'.)
Leiomyoma variant — There are a number of leiomyoma variants that manifest some facets of malignancy, yet lack others. For example, they may metastasize, but not be locally invasive and be histologically benign. Some of these variants show no facets of malignancy. These lesions appear to be exceedingly rare. (See "Variants of uterine leiomyomas (fibroids)".)
Other etiologies — Pregnancy is readily distinguishable from other uterine masses with measurement of a serum human chorionic gonadotropin and/or pelvic sonography. (See "Clinical manifestations and diagnosis of early pregnancy", section on 'Diagnosis'.)
Hematometra, a collection of blood within the uterine cavity, occurs most often following after an intrauterine procedure and/or in women with cervical stenosis and is diagnosed with pelvic imaging. (See "Overview of pregnancy termination", section on 'Hematometra'.)
Adenomatoid tumors are an uncommon type of mass of the female reproductive tract that can be seen in the myometrium or in the adnexa (the most common place is actually next to the fallopian tube) [83]. They are mesothelial proliferations and are not histologically related to adenomyosis. They may grossly mimic leiomyomas.
In addition, fibroids must be differentiated from other etiologies of abnormal uterine bleeding, pelvic pain, and infertility. (See "Approach to abnormal uterine bleeding in nonpregnant reproductive-age women" and "Postmenopausal uterine bleeding" and "Clinical features and diagnosis of pelvic inflammatory disease" and "Overview of infertility".).
Malignant disease
Sarcoma — Uterine sarcomas are rare. The incidence was 3 to 7 per 100,000 United States (US) population from 1989 to 1999 [84], based upon data from the Surveillance, Epidemiology and End Results (SEER) US national cancer database. The median age at diagnosis is approximately 60 years old. The three most common types of uterine sarcomas are clinically indistinguishable: leiomyosarcoma, endometrial stromal sarcoma, and undifferentiated endometrial sarcoma. The prognosis of sarcoma varies somewhat by histologic type, but, in general, the prognosis is poor compared to other gynecologic malignancies. (See "Differentiating uterine leiomyomas (fibroids) from uterine sarcomas".)
Carcinosarcoma — Uterine carcinosarcomas are rare and highly aggressive tumors with a poor prognosis. The incidence of carcinosarcomas in US women age 35 years or older is approximately 1 to 4 per 100,000 US population. The median age at diagnosis is approximately 62 to 67 years old.
Historically, uterine carcinosarcoma was classified as a type of uterine sarcoma, and was termed malignant mixed müllerian tumor or mixed mesodermal sarcoma. However, these tumors are now classified as carcinomas since they derive from a monoclonal cancer cell that exhibits sarcomatous metaplasia, rather than a mixture of carcinoma and sarcoma. In addition, the epidemiology, risk factors, and clinical behavior associated with carcinosarcoma also suggest a closer relationship to endometrial carcinoma than to sarcoma. (See "Clinical features, diagnosis, staging, and treatment of uterine carcinosarcoma", section on 'Epidemiology and risk factors' and "Clinical features, diagnosis, staging, and treatment of uterine carcinosarcoma", section on 'Pathology'.)
Endometrial carcinoma — Endometrial carcinoma may also result in abnormal uterine bleeding and a uterine mass. However, the diagnosis is typically made with endometrial sampling and imaging usually shows a thickened endometrium; if a mass is present, it is generally confined to the endometrium, except in women with advanced disease.
NATURAL HISTORY
Premenopausal women — With modern pelvic imaging, we have achieved an increased appreciation of the variability of growth and shrinkage of leiomyomas among women of reproductive age [14,85,86]. Prospective studies have found that between 7 to 40 percent of fibroids regress over six months to three years [14,85]. In one prospective study of 64 women (mean age 44 years) with fibroids, the average growth rate was 1.2 cm in diameter over 2.5 years (range 0.9 to 6.8 cm) [85]. As an example, a study that followed 72 women with a total of 262 fibroids with magnetic resonance imaging reported a median growth rate of 9 percent at six-month follow-up. [14]. There was wide variation in the growth of individual fibroids across all study participants (range -89 percent to +138 percent) and for different fibroids within each woman. Another example was a prospective study in which 36 women with a total of 101 fibroids were evaluated with magnetic resonance imaging at three-month intervals for one year [87]. Increase in volume of ≥30 percent in a three-month period was found in 37 myomas; rapid growth was more likely in tumors that were ≤5 cm in diameter. There is also an increased appreciation of postpartum regression of fibroids [27,32].
Postmenopausal women — Relief of menstrual bleeding symptoms related to fibroids occurs at the time of menopause, when menstrual cyclicity stops and steroid hormone levels wane. Most, but not all, women have shrinkage of leiomyomas at menopause.
Women on hormone therapy — Use of postmenopausal hormone therapy may cause some women with leiomyomas to continue to have symptoms after menopause. The risk of symptoms may depend, in part, on the location of the fibroid (higher if submucosal [88]) and type of estrogen preparation (higher with transdermal estrogen in some studies [89,90], but not others [91]).
A systematic review including five randomized controlled trials found that postmenopausal hormone therapy was associated with some myoma growth, but this typically occurred without clinical symptoms [92]. These findings were confirmed in a subsequent prospective study [93]. Thus, the presence of leiomyomas is not a contraindication to use of postmenopausal hormone therapy and postmenopausal hormone therapy does not lead to development of new symptomatic fibroids in most women. (See "Menopausal hormone therapy: Benefits and risks", section on 'Uterine leiomyomas'.)
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●Basics topics (see "Patient information: Uterine fibroids (The Basics)")
●Beyond the Basics topics (see "Patient information: Uterine fibroids (Beyond the Basics)")
SUMMARY AND RECOMMENDATIONS
●Uterine leiomyomas (fibroids or myomas) are the most common pelvic tumor in women (cumulative incidence by age 50 of >80 percent for black women and almost 70 percent for white women). The incidence of leiomyomas parallels the life cycle changes of the reproductive hormones estrogen and progesterone. (See 'Prevalence' above and 'Race' above.)
●Leiomyomas are benign monoclonal tumors arising from the smooth muscle cells of the myometrium. Fibroids are often described according to their location in the uterus (submucosal, intramural, subserosal, cervical). (See 'Prevalence' above.)
●Symptoms attributable to uterine myomas can generally be classified into three distinct categories: abnormal uterine bleeding, pelvic pressure and pain, reproductive dysfunction. (See 'Clinical manifestations' above.)
●The presumptive diagnosis of uterine myomas is usually based upon the finding of an enlarged, mobile uterus with an irregular contour on bimanual pelvic examination. Typically, an imaging study is used to confirm the diagnosis and exclude the possibility of another type of uterine mass or an adnexal mass. (See 'Diagnosis' above.)
●Transvaginal ultrasound is the most widely used imaging modality for evaluating fibroids due to its availability and cost-effectiveness. Saline infusion sonography (sonohysterography) improves characterization of the extent of protrusion into the endometrial cavity by submucous myomas and allows identification of some intracavitary lesions not seen on routine ultrasonography. (See 'Imaging' above.)
●Relief of symptoms related to fibroids usually occurs at the time of menopause, when menstrual cyclicity stops and steroid hormone levels wane. Most, but not all, women have shrinkage of leiomyomas at menopause. Use of postmenopausal hormone therapy may cause some women with leiomyomas to continue to have symptoms after menopause. Hormone therapy may be associated with an increase in size of existing myomas, but not with the development of new myomas. (See 'Postmenopausal women' above and 'Women on hormone therapy' above.)