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).

Description

• 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:
  • Upregulation of hormone receptors, particularly estrogen and progesterone
  • Excessive production of extracellular matrix (hence "fibroids")
• 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

• 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
• Hypertension

References:^[1][2][3][4]

Leiomyomas are classified according to their location within the uterus:

1. Intramural leiomyoma (most common)
2. Subserosal leiomyoma
3. Submucosal leiomyoma
   • Myoma in statu nascendi: expands through the cervical canal, causing labor-like pain
4. Diffuse uterine leiomyomatosis

References:^[1]

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

1. Abnormal menstruation
   • Hypermenorrhea, menorrhagia, metrorrhagia (possibly associated anemia)
   • Dysmenorrhea
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
   • Infertility
   • Dyspareunia

References:^[1]

• 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

References:^[5][1]

	Uterine leiomyoma	Adenomyosis	Endometriosis
Definition	Benign smooth muscle tumors within the uterine wall (myometrium)	Smooth muscle cells and endometrial glandular tissue within the uterine wall	Benign endometrial tissue outside the uterus
Risk factors	Early menarche Nulliparity	Early menarche Increased parity Previous uterine surgery	Retrograde menstruation
Uterine features	Irregularly enlarged, firm uterus	Uniformly enlarged uterus	Typically no uterine enlargement

• Uterine fibroids, adenomyosis, and endometriosis may be present simultaneously in the same patient.
• See also differential diagnosis of dysmenorrhea and menorrhagia and benign tumors of the endometrium

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

References:^[7]

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

References:^[1][8]

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