Fibroids (Uterine Leiomyoma)

Fibroids (uterine leiomyomas) are benign tumours of the smooth muscle cells of the uterus, with a thin capsular covering. They start as multiple, single cell seedlings distributed throughout the uterine wall. These then increase in size very slowly over many years, stimulated by oestrogens. As the fibroid grows, the central areas may not receive an adequate blood supply and undergo benign degeneration often followed by calcification. Fibroids are classified according to their position within the uterine wall:

• Intramural (70%)
• Growing into the uterine cavity; either submucosal, pedunculated submucosal or pedunculated vaginal (10%)
• Growing outwards from the uterus (20%); can be:
  • Cervical
  • Subserous
  • Intraligamentous
  • Pedunculated subserous (abdominal)

Most uterine fibroids are asymptomatic but they can cause significant morbidity, including prolonged or heavy menstrual bleeding, pelvic pressure or pain and reproductive dysfunction.¹ Fibroids almost certainly don't undergo malignant change to a sarcoma but tumours assumed to be benign fibroids are very occasionally later found to be uterine sarcomas.²

• Uterine fibroids are the most common non-cancerous tumours in women of childbearing age.
• Uterine fibroids are the single most common indication for hysterectomy. They are clinically apparent in up to 25% of women.
• Fibroids are more common in women with a higher body mass index and in non-smokers.
• Fibroids are 3 times more common in black American women than white women. Black women tend to be younger at the time of diagnosis and at hysterectomy. Asian women have a lower incidence of symptomatic uterine fibroids.
• Although they have been reported occasionally in adolescents, most women are in their 30s or 40s when the myomas become symptomatic. The incidence increases with age up to the menopause.
• Pregnancy and the use of oral contraceptives decrease the risk of fibroids.

• Up to half of women with fibroids have no symptoms. The presence of symptoms depends on their size, position and condition.
• Usually present between ages 30 and 50.
• Abnormal menstruation: excessive or prolonged heavy periods can cause iron deficiency anaemia and therefore lethargy and pallor. Submucosal fibroids are more likely to cause menorrhagia.
• Pedunculated submucosal fibroid can cause persistent intermenstrual bleeding.
• Pelvic pain: dysmenorrhoea; acute pain occurs when fibroid degenerates or there is torsion of a pedunculated fibroid. May cause dyspareunia.
• Pressure symptoms: an enlarging uterus may cause lower abdominal cramps, discomfort, and heaviness. Pressure on bowel may cause constipation and pressure on bladder may cause urinary frequency.
• May present with recurrent miscarriage or infertility.
• Examination:
  • Palpable abdominal mass arising from the pelvis
  • Enlarged, often irregular uterus palpable on bimanual pelvic examination
  • Signs of anaemia due to menorrhagia

Fibroids are so common that other more serious causes of abnormal bleeding or pelvic mass can often co-exist and need to be excluded. The differential diagnosis for fibroids depends on the symptoms they are causing but includes:

• Dysfunctional uterine bleeding
• Endometrial polyps, endometrial carcinoma
• Endometriosis
• Chronic pelvic inflammatory disease
• Tubo-ovarian abscess
• Uterine sarcoma
• Ovarian tumour
• Pelvic masses: other causes of a pelvic mass include tumour of large bowel, appendix abscess, diverticular abscess
• Pregnancy

• Pregnancy test may be indicated.
• Full blood count (anaemia), iron studies.
• Pelvic ultrasound: to confirm the presence and size of a fibroid, exclude other causes of a pelvic mass, and exclude possible complications such as urinary tract obstruction causing hydronephrosis. Transvaginal ultrasound is more accurate.
• MRI: occasionally required if ultrasound not definitive in assessing depth when hysteroscopic removal being considered.
• Endometrial sampling: for histology in the assessment of abnormal uterine bleeding.
• Hysteroscopy: with biopsies.

Treatment is only required if symptomatic, as long as other causes of pelvic masses and abnormal bleeding have been excluded.

Drugs

• Non-steroidal anti-inflammatory agents, e.g. mefenamic acid to reduce menstrual blood loss and dysmenorrhea
• Antifibrinolytic agents, e.g. tranexamic acid, to reduce menorrhagia
• Combined oral contraceptive if women also requires effective contraception
• Danazol reduces menorrhagia by suppressing gonadotropin secretion and abolishing cyclical ovarian function
• Gonadotropin-releasing hormone (GnRH) agonists:
  • Produce reduction in size of fibroid in the region of 50% within 3 months but once discontinued, fibroids regrow to their former size within about 2 months; therefore mainly useful preoperatively.
  • They are associated with significant side effects including amenorrhoea, menopausal symptoms and bone loss that can lead to osteoporosis in long term use.

Surgical

Surgery is indicated when there is excessively enlarged uterine size, pressure symptoms are present or when medical management is not sufficient to control symptoms or infertility.

• Myomectomy:
  • Used in patients who wish to maintain their reproductive potential or keep their uterus. However, this may be found at surgery not to be a viable option.
  • Laparoscopic myomectomy is the best treatment option for symptomatic women with uterine fibroids who wish to maintain their fertility.³
  • Hysteroscopic myomectomy is an established surgical procedure for women with excessive uterine bleeding, infertility or repeated miscarriages.³
  • Myomectomy is often performed via a hysteroscope for submucosal fibroids and using laparoscopy for subserous fibroids.
  • There is a risk of excessive bleeding and a risk of requiring hysterectomy at the time of the operation. Therefore blood should be cross-matched pre-op and the patient should consent (on the consent form) to hysterectomy should the need arise.
  • Myomectomy carries an annual recurrence rate of 2-3%.⁴
• Pedunculated vaginal fibroids may be removed vaginally but biopsy is essential to exclude a sarcoma in women over 60 years.
• Hysteroscopic endometrial ablation; for women presenting with menorrhagia.
• Total hysterectomy:
  • Has been the mainstay of treatment for many years eliminating both symptoms and the possibility of recurrence.
  • In women who have completed their family, hysterectomy remains the most effective treatment for excessive uterine bleeding.⁵
  • It is also indicated when there are many fibroids.
  • If these are small then the vaginal route is appropriate but if they are large (especially if intraligamentous) then laparotomy is indicated with preservation of ovaries if possible.⁶
  • NICE recommends that laparoscopic techniques for hysterectomy (e.g. laparoscopically-assisted vaginal hysterectomy, laparoscopic hysterectomy, laparoscopic supracervical hysterectomy and total laparoscopic hysterectomy) appear to be sufficiently safe and effective adequate to support their use. There is however a higher risk of urinary tract injury and of severe bleeding in comparison with open surgery.⁷
• Uterine artery embolisation:
  • Is both effective and relatively safe for women who no longer wish to have children.⁸
  • Ensuring the tumour is a benign fibroid and not a malignant sarcoma is essential prior to uterine artery embolisation.²
  • Compared with uterine artery embolisation (UAE), hysterectomy is associated with better improvement in pelvic pain. However UAE is a good alternative to hysterectomy.⁵

NICE does not currently recommend laparoscopic laser myomectomy, magnetic resonance image-guided percutaneous laser ablation or magnetic resonance image-guided transcutaneous focused ultrasound for the treatment of uterine fibroids.^9,10,11

• Iron-deficiency anaemia
• Bladder frequency, constipation (due to increased pelvic pressure)
• Hyaline degeneration (asymptomatic)
• Torsion of pedunculated fibroid
• Ureteral obstruction causing hydronephrosis
• Infertility; may occur as a result of narrowing of the isthmic portion of the fallopian tube or as a consequence of interference with implantation (especially with submucosal fibroids)
• In pregnancy:
  • Recurrent miscarriage
  • Fetal malpresentation
  • Red degeneration: presents with fever, pain and vomiting
  • Intrauterine growth retardation
  • Premature labour
  • Postpartum haemorrhage
  • Hydronephrosis

• Typically regression at the menopause and so symptoms then resolve, but will continue if on hormone replacement therapy.¹²