eMedicine Specialties > Radiology > Obstetrics/Gynecology
Leiomyoma, Uterus (Fibroid)
Updated: May 6, 2008
Introduction
Background
Leiomyomas are benign tumors of the uterus.
For excellent patient education resources, visit eMedicine's Women's Health Center. Also, see eMedicine's patient education article Fibroids.
Transabdominal sagittal sonogram shows a heterogeneous but predominately hypoechoic posterior uterine fibroid.
Coronal T2-weighted MRI shows an enlarged uterus with multiple fibroids.
Pathophysiology
Leiomyomas arise from the overgrowth of smooth muscle and connective tissue in the uterus. A genetic predisposition exists. Histologically, a monoclonal proliferation of smooth muscle cells occurs.
Evidence of an apparent hormonal dependency includes the following:
- Estrogen and progestin receptors are present in fibroids.
- Elevated estrogen levels may cause fibroid enlargement. During the first trimester of pregnancy, 15-30% of fibroids may enlarge and then shrink in puerperium. Some fibroids may decrease in size during pregnancy.
- Fibroids shrink after menopause. Some regrowth may occur with hormonal therapy.
Frequency
United States
Leiomyoma is the most frequently diagnosed gynecologic tumor, occurring in 20-50% of women older than 30 years.1
Mortality/Morbidity
Rarely, uterine leiomyoma may undergo malignant degeneration to become a sarcoma. The true incidence of malignant transformation is difficult to determine, because leiomyomas are common, whereas malignant leiomyosarcomas are rare and can arise de novo. The incidence of malignant degeneration is less than 1.0% and has been estimated to be as low as 0.2%.
Infertility may occur as a result of narrowing of the isthmic portion of the fallopian tube or as a consequence of interference with implantation, especially inference caused by submucosal fibroids.
Complications during pregnancy include spontaneous abortion, intrauterine growth retardation, preterm labor, uterine dyskinesia or inertia during labor, obstruction of the birth canal, postpartum hemorrhage, and hydronephrosis.
Race
Leiomyomas occur more commonly in black women (3:1) than they do in white women (9:1). A genetic predisposition exists.2
Sex
Uterine leiomyomas occur only in females.
Age
Leiomyomas occur most commonly in women older than 30 years, but they may develop in females of any age.
Anatomy
Most leiomyomas occur in the fundus and body of the uterus; only 3% occur in the cervix. The fibroids may be solitary, multiple, or diffuse.
Most fibroids (95%) are intramural, being located in the middle of the myometrium. Subserosal, or exophytic, fibroids are located in the subserosal layer and tend to cause a focal bulge in the exterior surface of the uterus; they can become pedunculated. Rarely, subserosal fibroids occur in the broad ligament. Submucosal, or subendometrial, fibroids are the least common. They distort the overlying endometrium and can become extruded or pedunculated (ie, fibroid polyps) in the endometrial canal.
Presentation
Most women with fibroids are asymptomatic. Only 10-20% of patients require treatment.
Fibroid symptoms are related to the number of tumors, as well as to their size and location. Symptoms may include the following:
- Bleeding - Menorrhagia, with an increased amount and duration of flow, is the most common symptom. Menorrhagia may result in severe anemia and can be life threatening, although this is rare. Menorrhagia usually results from the erosion of a submucosal fibroid into the endometrial cavity. Rarely, dilated veins on the surface of a subserosal, pedunculated fibroid can cause sudden, massive intraperitoneal bleeding.
- Pain - Women may experience abdominal cramping. Pain usually is felt during menstruation. Less often, pain occurs intermenstrually.
- Pressure - Urinary frequency, urgency, and/or incontinence result from pressure on the bladder. Constipation, difficult defecation, or rectal pain results from pressure on the colon. Abdominal cramping results from pressure on the small bowel. Generalized pelvic and/or lower abdominal discomfort may be present.
- Other - Rare cases of secondary polycythemia, cured with hysterectomy, are reported. Infertility and/or complications of pregnancy may occur. Submucosal fibroids may affect fertility (see Mortality/Morbidity). A subserosal fibroid can twist on its pedicle, resulting in necrosis and pain.
Preferred Examination
The preferred imaging modality for the evaluation of uterine fibroids is ultrasonography (US), specifically, transabdominal and transvaginal US.
Calcified fibroids are often depicted on conventional radiographs of the pelvis. In some patients, magnetic resonance imaging (MRI) provides additional information. The role of computed tomography (CT) scanning is limited. Calcifications may be more visible on CT scans than on conventional radiographs because of the superior contrast differentiation achieved with CT scanning.3,4
Limitations of Techniques
In the detection of uterine fibroids, CT scanning is limited by the similar attenuation characteristics of fibroids and healthy myometrium, although some fibroids may be hypoattenuating. Fibroid calcifications can be depicted on CT scans.
Differential Diagnoses
Ovary, Malignant Tumors
Uterine Cancer
Uterine Fibroid Embolization
Uterus, Adenomyosis
Other Problems to Be Considered
Normal ovary - May be confused with fibroids at US
Ovarian mass - Hemorrhagic cyst, endometrioma, dermoid, cystadenoma, malignant tumor
Uterine leiomyosarcoma - Rare, arise de novo or as a result of the malignant degeneration of a uterine fibroid
Adenomyosis - May be difficult to distinguish from multiple small fibroids
Myometrial contraction - Especially during pregnancy
Necrotic fibroids - May mimic intrauterine gestational sac, intrauterine fluid collection, hydatiform mole
More on Leiomyoma, Uterus (Fibroid) |
 Overview: Leiomyoma, Uterus (Fibroid) |
| Imaging: Leiomyoma, Uterus (Fibroid) |
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| Multimedia: Leiomyoma, Uterus (Fibroid) |
| References |
| Further Reading |
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References
Lee DW, Gibson TB, Carls GS, et al. Uterine fibroid treatment patterns in a population of insured women. Fertil Steril. Feb 25 2008;[Medline].
Huyck KL, Panhuysen CI, Cuenco KT, et al. The impact of race as a risk factor for symptom severity and age at diagnosis of uterine leiomyomata among affected sisters. Am J Obstet Gynecol. Feb 2008;198(2):168.e1-9. [Medline].
Dahnert W. Dahnert's Radiology Review Manual. 4th ed. Baltimore, Md: Williams & Wilkins; 1996:884-5.
Weissleder R, Wittenberg J. Primer of Diagnostic Imaging. St Louis, Mo: Mosby-Year Book; 1994:302.
Callen PW, ed. Ultrasonography in Obstetrics and Gynecology. 5th ed. Philadelphia, Pa: Saunders Elsevier; 2007.
Kurtz AB, Middleton WD. Ultrasound. St Louis, Mo: Mosby; 1996.
Sauerbrel EE, Nguyen KT, Nolan RL. A Practical Guide to Ultrasound in Obstetrics and Gynecology. 2nd ed. Philadelphia, Pa: Lippincott-Raven; 1998:52-8.
Kaminski P, Gajewska M, Wielgos M, et al. Laparoscopic treatment of uterine myomas in women of reproductive age. Neuro Endocrinol Lett. Feb 2008;29(1):163-7. [Medline].
Siskin GP, Beck A, Schuster M, et al. Leiomyoma infarction after uterine artery embolization: a prospective randomized study comparing tris-acryl gelatin microspheres versus polyvinyl alcohol microspheres. J Vasc Interv Radiol. Jan 2008;19(1):58-65. [Medline].
Kim HS, Paxton BE, Lee JM. Long-term efficacy and safety of uterine artery embolization in young patients with and without uteroovarian anastomoses. J Vasc Interv Radiol. Feb 2008;19(2 Pt 1):195-200. [Medline].
Ahmad A, Qadan L, Hassan N, et al. Uterine artery embolization treatment of uterine fibroids: effect on ovarian function in younger women. J Vasc Interv Radiol. Oct 2002;13(10):1017-20. [Medline].
Further Reading
Related eMedicine topics:
Gynecologic Myomectomy
Uterine Fibroid Embolization
Leiomyoma, Uterus (Fibroid)
Uterine Cancer
Keywords
leiomyoma, uterine; uterine leiomyoma; myoma, uterus; fibromyomas, uterus; leiomyomata; benign tumors of the uterus; fibroids; myomectomy; subserosal fibroid; exophytic fibroid; submucosal fibroid; subendometrial fibroid; intramural fibroid
