• 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).


  • A benign, hormone-sensitive smooth muscle tumor of the uterus
  • Can be submucosal, intramural, or subserosal
  • Arises from a single myometrial cell (monoclonal growth) and causes:
  • Results in an overgrowth of smooth muscle cells and connective tissue (often multiple tumors)
  • The myometrium also develops vascular changes (e.g., increased arterioles and venules, dilated veins).
  • The most common tumor of the female genital tract.


Predisposing factors



Leiomyomas are classified according to their location within the uterus:


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
  3. Reproductive abnormalities



  • Ultrasound (best initial test)
    • Concentric, hypoechoic, heterogeneous tumors
    • Calcifications or cystic areas suggest necrosis.
    • Saline-infused sonography: can be used to better visualize submucosal and intramural fibroids
  • Hysteroscopy: to assess submucosal fibroids
  • MRI: to evaluate the uterus and ovaries for potentially complicated surgical cases and visually differentiate between leiomyomas, adenomyomas, and adenomyosis



  • Macroscopic
    • Grayish-white surface
    • Homogeneous; 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

Differential diagnosis of uterine leiomyoma
Factors Uterine leiomyoma (fibroids) Adenomyosis Endometriosis Uterine polyps Uterine leiomyosarcoma [6][7]
  • Benign smooth muscle tumors within the uterine wall (submucous, subserous, or in myometrium)
  • Overgrowth of localized endometrial tissue attached to the inner wall of the uterus, usually benign [8]
Risk factors
  • Retrograde menstruation
Clinical features
  • Symptoms similar to uterine fibroids
  • Menstrual irregularities
  • Postmenopausal bleeding
  • Pelvic pain
Uterine findings
  • Irregularly enlarged, firm
  • Uniformly enlarged
  • Typically not enlarged
  • Typically not enlarged
  • Rapidly enlarging
  • Smooth muscle tissue in a whorled pattern with well-demarcated borders
  • Pedunculated or sessile
  • Single or multiple
  • Length varies (up to many centimeters in size)

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.

Interventional therapy

  • Uterine fibroid embolization: uterine artery embolization
    • Procedure: injection of polyvinyl alcohol (PVA) into the arteries that supply blood to the fibroid, causing it to shrink; ¼ of patients may require further invasive treatment
    • Indications:
      • Continued heavy bleeding and/or severe pain with insufficient response to medical treatment
      • Contraindications to surgery or personal preference to avoid surgery
      • No wish to conceive in the future

Surgical therapy

  • Indications: rapidly growing fibroid, recurrent refractory bleeding: secondary to medical therapy, severe symptoms
  • Procedures
    • Myomectomy: excision of subserosal or intramural fibroids (preferred for women planning future pregnancies)
    • Hysterectomy: definitive treatment




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

Special patient groups

Uterine leiomyomas during pregnancy