• Clinical science

Uterine leiomyoma (Fibroid…)


Uterine leiomyomas (fibroids) are benign, hormone-sensitive uterine neoplasms. These tumors are classified as either submucosal (beneath the endometrium), intramural (within the muscular uterine wall of the uterus), or subserosal (beneath the peritoneum). Symptoms depend on the location, size, and number of myomas, and include menstrual abnormalities (menorrhagia), features of mass effects (e.g., back/abdominal/pelvic pain or bladder and bowel dysfunction), and infertility. Physical examination and sonohysterography are used to establish the diagnosis. Treatment for symptomatic patients includes surgery (myomectomy or hysterectomy) as well as interventional (uterine artery embolization) and/or medical therapy (GnRH agonists).


Uterine leiomyomas are the most common tumor of the female genital tract.

Predisposing factors

  • Nulliparity
  • Early menarche (< 10 years old)
  • Age: 25–45 years
  • Race: Black women are at increased risk.
  • Obesity
  • Family history
  • Hypertension



Leiomyomas are classified according to their location within the uterus:

  1. Intramural leiomyoma (most common)
  2. Subserosal leiomyoma
  3. Submucosal leiomyoma
  4. Diffuse uterine leiomyomatosis


Clinical features

Most women have small, asymptomatic fibroids. Symptoms depend on the number, size, and location of leiomyomas.

  1. Abnormal menstruation
  2. Features of mass effect
    • Enlarged ; , firm and irregular uterus during bimanual pelvic examination
    • Back or pelvic pain/discomfort
    • Urinary tract or bowel symptoms (e.g., urinary frequency/retention; , constipation; , features of hydronephrosis)
  3. Reproductive abnormalities



  • Ultrasound (best initial test)
    • Concentric, hypoechoic, heterogeneous tumors
    • Calcifications or cystic areas suggest necrosis.
    • Doppler sonography of intramural fibroids: marked vascularization at the tumor borders, but little vascularization in the center
  • MRI: to evaluate the uterus and ovaries for potentially complicated surgical cases and visually differentiate between leiomyomas, adenomyomas, and adenomyosis



  • Macroscopic
    • Grayish-white surface
    • Homogenous; tissue bundles on cross section partly in a whorled pattern
    • Some leiomyomas may involve regressive changes: scar formation, calcification, and cysts
  • Microscopic: Smooth muscle tissue, consisting of monoconal cells interspersed with connective tissue


Differential diagnoses

Uterine leiomyoma Adenomyosis Endometriosis
  • Benign smooth muscle tumors within the uterine wall (myometrium)
  • Benign endometrial tissue outside the uterus
Risk factors
  • Retrograde menstruation
Uterine features
  • Irregularly enlarged, firm uterus
  • Typically no uterine enlargement

See also differential diagnosis of dysmenorrhea and menorrhagia.

Uterine fibroids, adenomyosis, and endometriosis may be present simultaneously in the same patient!

The differential diagnoses listed here are not exhaustive.


Treatment should only be considered in symptomatic patients because of the side effects of medical therapy and surgery. The goal is to relieve symptoms. Perimenopausal women warrant expectant management in most cases.

Asymptomatic fibroids

  • Do not require treatment
  • Frequent follow-ups (approx. every 6–12 months) are necessary to monitor any potential growth.

Symptomatic fibroids

Medical therapy

Preoperative medical therapy may help reduce tumor size and decrease tumor vascularization.

  • Hormone therapy
    • Gonadotropin-releasing hormone (GnRH) agonists: e.g., leuprolide, goserelin
    • Estrogen-progestin contraceptive pills are controversial.
    • Exogenous progestins
    • Levonorgestrel-releasing intrauterine devices aid (to control heavy bleeding)
  • NSAIDs: to control pain
  • Antifibrinolytics (e.g., tranexamic acid): reduce bleeding
  • Androgenic agonists (e.g., danazol): suppress growth of fibroids but has many side effects (e.g., acne, edema, hair loss, etc.)
  • In cases of uncontrollable bleeding: ergot derivatives (methylergometrine), packed red blood cells

Surgical therapy

  • Indications: rapidly growing fibroid, recurrent refractory bleeding: secondary to medical therapy, severe symptoms
  • Procedures
    • Myomectomy: excision of subserosal or intramural fibroids
    • Hysterectomy: definitive treatment



  • Fibroid degeneration or torsion
  • Thromboembolism


We list the most important complications. The selection is not exhaustive.


  • Fibroids seldom degenerate into a malignancy.
  • Fibroids typically shrink after menopause.


Special patient groups

Uterine leiomyomas during pregnancy

  • Elevated concentrations of progestin and estrogen foster the growth of leiomyomas. Pain may be caused by:
  • Premature contractions
  • Depending on location and size:
  • Cervical leiomyoma: obstruction of the birth canal → indication for cesarean section
  • Postpartum: atonic hemorrhages
  • Puerperium: fibroid regression accompanied by calcification