Fibroids are benign smooth muscle neoplasms arising from myometrial cells. They are oestrogen and progesterone–sensitive, with an average growth rate of 0.5 cm/year.
They peak between 40 and 50 years of age.
- Risk
- Incidence increases with age during reproductive years (30-50 years of age)
- They stop growing and calcify during menopause
- African heritage
- Family history
- Overweight and obesity
- Early menarche
- Nulliparity
- Oestrogen and progesterone exposure
- Hormonal replacement therapy (HRT) can cause fibroids to grow
- Polycystic ovarian syndrome (PCOS)
- Incidence increases with age during reproductive years (30-50 years of age)
- Protective factors
- Risk decreases with parity
- Giving birth at an ealry age
- Combined oral contraceptives
- Smoking
- Pathophysiology
- Fibroids create a hyperestrogenic environment since they:
- Contain more estrogen receptors
- Convert less estradiol to estrone
- Contain more aromatase
- The effects of progestins are unclear
- Given alone they decrease growth
- Given with GnRH agonists they accelerate growth
- Fibroids create a hyperestrogenic environment since they:
- Signs and symptoms
- Abnormal bleeding
- Usually menorrhagia from submucosal fibroids
- This is the most common symptom
- Dysmenorrhea
- Dyspareunia
- Noncyclical pelvic pain
- Infertility (2-3% cases of infertility)
- Acute pelvic pain
- Due to degeneration or torsion of pedunculated leiomyomas
- Abnormal bleeding
- Physical examination
- Uterine enlargement with irregular contour
- Non-tender or minimally tender
- Investigations
- Transvaginal ultrasound is the imaging modality of choice
- Hyperechoic or hypoechoic discrete masses
- Doppler shows a rim of blood flow around the fibroid
- Hysterosonography (saline infusion sonography) for submucosal fibroids
- Hysteroscopy for submucosal fibroids
- Urine B-hCG
- MRI for large or numerous fibroids, to plan treatment, and to differentiate from adenomyosis or other uterine anomalies
- Complete blood count to assess for anaemia due to menorrhagia
- Coagulation panel if a coagulopathy is suspected
- Transvaginal ultrasound is the imaging modality of choice
- Treatment
- Levonorgestrel-releasing intrauterine system (Mirena, LNG-IUS) is the first-line treatment
- For pain and menorrhagia
- Sufficient distortion of the uterus by firboids can dislodge the intrauterine device
- NSAIDs for pain and dysmenorrhoea
- Combined oral contraceptives for pain and menorrhagia
- GnRH agonists (leuprolide, nafarelin, goserelin, or buserelin) as short term therapy
- They reduce the size of the fibroids
- ACOG recommends not to use these for more than 6 months without add-back therapy
- Surgery
- Myomectomy is preferred if fertility needs to be preserved
- Uterine artery embolization
- Hysterectomy
- Levonorgestrel-releasing intrauterine system (Mirena, LNG-IUS) is the first-line treatment
- Complications
- Anaemia due to menorrhagia
- Pressure symptoms
- Urinary retention, frequency, and hydronephrosis
- Constipation or bowel obstruction (rare)
- Pelvic venous congestion and thrombosis
- Degenerative changes
- Subfertility
- Particularly with submucosal fibroids
- Obstetric
- Miscarriage
- Preterm delivery
- Fetal malpresentation
- Fetal growth restriction
- Abnormal placentation
- Malignant transformation to a leiomyosarcoma (rare)
Fibroid degeneration
| Type of Degeneration | Description |
|---|---|
| Hyaline degeneration (most common, ~60%) | This is the most common degeneration. It is clinically insignificant. Smooth muscle fibers are replaced by homogeneous eosinophilic hyaline material. |
| Cystic degeneration (~4%) | This occurs mainly in post-menopausal women. It is due to necrosis. Liquefaction of hyaline areas → cystic spaces filled with serous fluid. May mimic ovarian cysts or molar pregnancy in women of childbearing age |
| Red (carneous) degeneration | Acute hemorrhagic infarction of the fibroid often occurs during pregnancy (2° to venous thrombosis or arterial compromise). An important cause of acute abdomen in pregnancy |
| Myxoid degeneration | Accumulation of myxoid (gelatinous, mucoid) material within fibroid. |
| Fatty (lipomatous) degeneration | Deposition of fat within fibroid tissue. |
| Calcific (dystrophic) degeneration | Calcium deposits within fibroid (especially post-menopausal). |
| Suppurative degeneration | Rare. Infection of necrotic fibroid tissue (especially after uterine instrumentation or postpartum). |
| Sarcomatous degeneration | Malignant transformation. |