• 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).



Predisposing factors

  • Nulliparity
  • Early menarche (< 10 years old)
  • Age: 25–45 years
    • Fibroids are largely found in women of reproductive age
    • influenced by hormones (i.e., estrogen, growth hormone, and progesterone)
    • During menopause, hormone levels begin to decrease and leiomyomas begin to shrink
  • Increase incidence in African Americans
  • Obesity
  • Family history



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.
  • 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 in a whorled pattern with well-demarcated borders, consisting of monoclonal cells interspersed with connective tissue


Differential diagnoses

Uterine leiomyoma Adenomyosis Endometriosis
Risk factors
  • Retrograde menstruation
Uterine features
  • Irregularly enlarged, firm uterus
  • Typically no uterine enlargement

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.)

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



  • Malignant transformation to leiomyosarcoma is rare
  • Fibroid torsion
  • Thromboembolism
  • Fibroids typically shrink after menopause.


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

Special patient groups

Uterine leiomyomas during pregnancy