Uterine fibroids (Leiomyomas)

Question 1

What are uterine fibroids (Leimyomas)?

Answer 1

Uterine fibroids are benign tumours that arise from the smooth muscle layer of the uterus (myometrium). They are the most common benign pelvic tumours in women of reproductive age and are promoted and maintained by exposure to *oestrogen and progesterone

They can be single, or multiple, and their size varies from a few mm to 30 cm or larger

Question 2

Which two hormones control the proliferation and maintenance of uterine fibroids?

Answer 2

Oestrogen and Progesterone

Question 3

Epidemiology of uterine fibroids

a) . How common are uterine fibroids?
b) . Affects which age group the most?
c) . Which ethnicity of people is more susceptible to developing uterine fibroids?

Answer 3

a) . They are the most common benign uterine tumours in women and the leading cause of hysterectomy
b) . The incidence of uterine fibroids increases with age until the menopause with peak incidence in women in their 40s. They DON’T occur in pre-pubescent girls (i.e. girls before their puberty)
c) . More common in black women (African and Afro-Caribbean ethnicity)

Question 4

Why is the incidence of uterine fibroids lower in menopausal women?

Answer 4

Uterine fibroids proliferate and enlarge under the influence of oestrogens and progesterone. In menopausal women, there is a depletion in both of these hormones, so the fibroids shrink!

Question 5

Are uterine fibroids seen in pre-pubescent girls?

Answer 5

NO!!! as the levels of oestrogen and progesterone remain low until puberty, and fibroids are hormone-driven growths!

Question 6

Fibroids may develop anywhere within the myometrium of the uterus. There are 3 types of fibroids depending on their locations.

What are they?

Answer 6

3 types of uterine fibroids according to CKS: (see image)

Subserosal fibroids

• They develop near the outer serosal surface of the uterus and extend into the peritoneal cavity
• Usually asymptomatic
• If too large, they may cause symptoms due to compression on nearby structures e.g. urinary symptoms due to pressure on the bladder

Intramural fibroids

• They develop within the myometrium without extending predominately into the uterine cavity or peritoneal cavity
• May cause menorrhagia and dysmenorrhoea by interfering with the constriction of blood vessels during menstruation
  
  • Menstruation occurs as a consequence of intense vasoconstriction and coagulation in the spiral arteries leading to intense inflammation and partial necrosis, after which the functionalis layer of the endometrium separates from the underlying basalis and is shed with blood

Submucosal fibroids

• They develop near the inner mucosal surface of the uterus and extend into the uterine cavity - more likely to distort the uterine cavity!
• Even small submucosal fibroids may cause significant menorrhagia and dysmenorrhoea or reduce fertility

Question 7

Give 5 risk factors of uterine fibroids

Answer 7

Risk factors of uterine fibroids

Increasing age (the risk of fibroids increases progressively from puberty until the menopause)

Early puberty

Obesity

Black ethnicity (incidence is higher in black and Asian women)

FHx of uterine fibroids

Question 8

Give 2 protective factors of uterine fibroids

Answer 8

The risk of fibroids is reduced by pregnancy and decreases with an increasing number of pregnancies. POPs also appear to reduce the risk

Question 9

Give 5 complications of uterine fibroids

Answer 9

Non-pregnancy-related complications:

• Abnormal uterine bleeding (more common with submucosal fibroids) and anaemia
• Prolapsed fibroid
• Endocrine effects (polycythaemia, hypercalcaemia, hyperprolactinaemia)
• Torsion of a pedunculated fibroid

Pregnancy-related complications

• Infertility (most common with submucosal fibroids as they cause distortion of the uterine cavity)
• Acute abdominal pain secondary to ‘red degeneration’
  
  • ‘Red degeneration’ is a haemorrhagic infarction of the uterine fibroid, commonly occurs during pregnancy. It’s thought to be due to degenerative changes when rapid growth of a fibroid, promoted by high levels of sex hormones in pregnancy, outgrows its blood supply
• Malpresentation
• Placental abruption
• Intrauterine growth restriction
• Preterm labour
• Miscarriage

Question 10

Picture of a normal fibroid

Answer 10

Question 11

What are the clinical features of uterine fibroids?

Answer 11

Presentations:

• Most are asymptomatic!
• However, in those that are symptomatic:
  
  • Menorrhagia and anaemia
  • Pelvic pain
    
    • In some cases, fibroids may undergo ‘red degeneration’ during pregnancy, causing acute severe abdominal pain. Red degeneration is the result of rapid enlargement (due to pregnancy causing an increase in oestrogen levels) causing the fibroid to outgrow its blood supply, causing ischaemic and haemorrhagic necrosis
    • Another cause of severe abdominal pain is torsion of a pedunculated fibroid
  • Abdominal distention or distortion
  • Dyspareunia
  • Dysmenorrhoea
  • Urinary/ bowel symptoms - due to compression from the fibroids on the bladder and the rectum
    
    • Frequency, urgency, urinary incontinence, hydronephrosis
    • Bloating, constipation
  • Subfertility
  • Polycythaemia (rare) secondary to autonomous production of EPO
• On abdominal and bimanual pelvic examination:
  
  • A firm, enlarged, and irregularly shaped non-tender uterus is characteristic of uterine fibroids
    
    • The mass can be moved slightly from side-to-side
  • In cases of large tumours, a central irregular mass can be palpated on transabdominal examination

Question 12

What investigations would you carry out in a woman with suspected uterine fibroids?

Answer 12

Ix:

• 1st line Ix - *transabdominal and transvaginal USS to identify a pelvic mass or menorrhagia that is not responsive to conventional treatment
• Blood tests (FBC) to check for iron deficiency anaemia
• Pelvic MRI +/- hysteroscopy if concern about intramural fibroids or malignancy
  
  • Pelvic MRI is the best imaging modality to assess fibroids and useful at differentiating between leiomyomas (smooth muscle), adenomyosis (endometrial tissue in the myometrium), and adenomyomas (benign tumour variant of adenomyosis). Tends to be reserved for complicated cases or operative planning

Question 13

Give 5 differential diagnoses of uterine fibroids

Answer 13

Malignant causes of a pelvic mass - ovarian cancer, endometrial cancer, uterine sarcoma (e.g. leiomyosarcoma), GI/ urinary tract tumour

Benign causes of a pelvic mass - endometrial polyp, endometrial hyperplasia, adenomyosis

Pregnancy, urinary retention

Question 14

How do you manage fibroids?

Answer 14

• If asymptomatic –> no treatment needed, just arrange an annual follow up to monitor the size and growth of the fibroid
• Mx of menorrhagia
  
  • If fibroids < 3 cm in diameter –> 1st line: Levonorgestrel-releasing intrauterine system (LNG-IUS)
    
    • If LNG-IUS is contraindicated or intolerated –> give tranexamic acid/ NSAID (e.g. mefenamic acid)/ COCP/ cyclical progestogen
  • If fibroids >/= 3 cm in diameter
    
    • Same pharmacological Mx as above
      
      • If that doesn’t work –> uterine artery embolisation or surgery (myomectomy)
• Mx to shrink/ remove fibroids
  
  • GnRH agonists (reduce size of fibroids but this is only useful for short-term treatment) e.g. triptorelin
  • For definitive Mx –> surgery (myomectomy if the woman wishes to conceive in the future, OR hysterectomy if the woman’s family is completed)

Question 15

Give 3 complications of myomectomy?

Answer 15

Adhesions (most common)

Bladder injury

Uterine perforation

Question 16

When should you refer a woman with uterine fibroids?

Answer 16

• Suspected cancer pathway referral (2-week wait) if she has a pelvic mass associated with any other features of cancer e.g. unexplained bleeding or weight loss, or if there is radiological suspicion of malignancy
• Refer women with:
  • Complications such as compressive symptoms from large fibroids are present (e.g. dyspareunia, pelvic pain, constipation, or urinary symptoms)
  • Fertility or obstetric problems associated with fibroids
  • Fibroids that are palpable abdominally (due to a very large fibroid), or intracavity fibroids whose uterine length is measured at USS or hysteroscopy, greater than 12 cm

Question 17

A 34-year-old lady presents to the gynaecology department complaining of heavy, painful periods, and difficulty conceiving. She is concerned, as she and her husband would like to start a family soon. On further investigation, an ultrasound scan reveals a 4.5cm submucosal uterine fibroid. Which one of the following treatments is most appropriate to treat her fibroids?

a) . Hysterectomy
b) . Tranexamic acid
c) . Hysteroscopic endometrial ablation
d) . Levonorgestrel intrauterine system (IUS)
e) . Myomectomy

Answer 17

The answer is e - myomectomy

This lady has a large (> 3cm) submucosal fibroid which is likely to distort the shape of her uterus and contributing to her infertility. The only effective treatment for large fibroids causing problems with fertility is myomectomy if the woman wishes to conceive in the future

Question 18

A 37-year-old woman who is 15 weeks pregnant presents with abdominal pain. The pain came on gradually and has been getting progressively worse for 3 days. She is nauseated and has vomited twice this morning. She has a temperature of 38.4ºC, blood pressure is 116/82 mmHg and heart rate is 104 beats per minute. The uterus is palpable just above the umbilicus and a fetal heart beat is heard via hand-held Doppler. On speculum examination the cervix is closed and there is no blood. She has a history of menorrhagia due to uterine fibroids. This is her first pregnancy. What is the most likely diagnosis?

a) . Multiple pregnancy
b) . Fibroid degeneration
c) . Inevitable miscarriage
d) . N&V of pregnancy
e) . Heterotropic pregnancy

Answer 18

The answer is b - Fibroid degeneration (or ‘red degeneration)

Uterine fibroids are sensitive to oestrogen and can therefore grow during pregnancy. If the fibrous tissues outgrow their blood supply, they can undergo red or ‘carneous’ degeneration. This usually presents with low-grade fever, abdo pain and vomiting. The condition is usually managed conservatively with rest and analgesia and should resolve within 4-7 days.

Remember that oestrogen and progesterone are the chief pregnancy hormones. A woman will produce more oestrogen during one pregnancy than throughout her entire life when not pregnant.