Fibroids

 

Fibroids are uterine smooth muscle tumours each developed from a single muscle cell.  It is estimated that more than 30% of women would have one or more fibroids after the age of 30 but are not common in younger age groups. Accordingly increasing age up to the menopause is considered as one of the risk factors for increased prevalence of fibroids together with family history, racial origin, obesity as well as nulliparity. 

 

There is a 3-fold increased risk of developing fibroids with similar first degree family history. Furthermore fibroids are more common, multiple and larger in Afro-Caribbean women compared to other ethnic groups. As well body habitat is considered to be a predisposing factor. Women who weigh > 70 kg are 3 times more likely to develop fibroids than women <50 kg heavy.

 

An association between nulliparity, infertility and fibroids has been known or suspected for many years. Nulliparous women are more likely to have fibroids than parous women. In fact there is a inverse relationship between the number of pregnancies and fibroids. A nulliparous women is 4 times more at risk of developing fibroids than a woman who had 5 children. As well there is a double risk of fibroids in infertile woman but a causal relationship is still vague and needs stronger evidence.

 

Fibroids could be found totally or partly within the uterine cavity [submucous], within the muscle wall [intramural] or just underneath the serosal outer covering of the uterus [subserosal]

 

In many if not most cases fibroids give no symptoms and are chance findings during pelvic or ultrasound scan examinations. However when present symptoms usually depend on the number, size and location of the fibroids. 

• It has been reported that  30% of women with uterine fibroids have menstrual abnormalities. Both intracavitary and intramural fibroids could increase the endometrial surface area. However  vascular defects and impaired endometrial haemostasis could also be contributing factors. Heavier menstrual blood loss >200 ml is more associated  with fibroids  [40%] than blood loss in the region of  80-100 ml [10%] as shown in one study. This is reflected by the fact that  anaemia is more common in women with heavy menstrual loss associated with fibroids than menorrhagia due to other factors. 
• Pressure symptoms on neighbouring structures especially the urinary bladder leading to increased urinary frequency and urgency.
• Dysmenorrhoea or pelvic pain due to degeneration and torsion of a fibroid or possibly an associated adenomyosis could be a presentation. On the other hand red degeneration of fibroids during pregnancy could cause pain of different intensities mainly during the second trimester in up to 10% of the cases. However despite contradictory teaching prospective studies showed that in 80% of the cases fibroids showed reduction or no change in size during pregnancy.
• Repeated miscarriages and infertility have been attributed mainly to submucous fibroids. There are no randomised controlled studies to examine the effect of myomectomy on infertility. However few case series showed that removal of fibroids was followed by pregnancies in 30-80% of the cases.
• Abdominal mass or just increase in abdominal girth might be the only presenting symptoms.

Pelvic ultrasound scan examination is the most commonly used technique for diagnosing fibroids. They are often seen as hypoechoic masses with well defined margins and ring-like vascularisation on colour Doppler mapping.

---

Fibroids could be identified according to their location as:  

 

Submucous fibroids

 These are located either totally or partially within the uterine cavity and cause most of the bleeding and miscarriage problems encountered in the gynaecology clinic. Different investigators reported the presence of submucous fibroids in 6-34% of patients with abnormal uterine bleeding, 2-7% of women investigated for infertility and 1.5% of asymptomatic women undergoing hysteroscopic sterilisation.

 

They are graded into 3 subgroups

• grade 0 when all the fibroid is inside the uterine cavity
• grade 1 when more than 50% of the fibroid is within the cavity.
• grade 2 when less than 50% of the fibroid is within the cavity.

This is a practical classification as both grade 0 and 1 could be removed hysteroscopically without difficulty in most cases. As for grade 2 difficulties could be encountered as most of the fibroid is not within the cavity.  

The thickness of myometrial mantle between the fibroid and the overlying serosa should be considered as the controlling factor in offering or denying hysteroscopic resection for safety reasons.   

 

 

The above pictures show grades 0, 1 and submucosus fibroids after saline infusion. 

 

 

 

The first picture above is a rendered view of a uterus with a submucous fibroid with an overlying polyp. The neighbouring hysteroscopic picture confirmed the diagnosis as shown by ultrasound.

 

Please click on this link to see hysteroscopic resection of submucous fibroid:  http://www.youtube.com/watch?v=fZSi71pv7Uw

Subserous fibroids

 

These are fibroids located just underneath the outer serosa. They could grow to very large size and retain connection to the uterus with only a narrow stalk. Usually they cause no menstrual or infertility problems but might cause pressure symptoms related to neighbouring organs. Broad ligament fibroids might fall into this group.

 

 

 

The above 4 pictures respecively show: Oblique view showing anterior subserous fibroid pushing into the bladder and causing increased frequency and urgency of micturition.    Axial view in the transverse pelvic plane showing a subserous fibroid on the left side of a uterus. The laparoscopic picture shows a large pedunculated subserous fibroid with a broad stalk and prominent superficial blood vessels on the left side. A large anterior intramural fibroid and a small subserous fibroid are seen. The last ultrasound picture shows the same fibroid (as in the neighbouring laparoscopy picture) attached to the uterus by a thick vascular stalk

Intramural fibroids

 

These are fibroids located totally or maximally within the muscle wall itself and form the majority of diagnosed fibroids. They could be small or large, single or multiple. They are often associated with adenomyosis. It is reported that fibroids, adenomyosis and polyps could be found together and the presence of one would increase the chance to 80% of finding one of the other two.  

In recent years research showed that intramural fibroids larger than 5 cm in diameter and those close to the cervix and fallopian tubes could affect fertility without involvement of the uterine cavity. As well some recent work showed a negative effect of these fibroids on IVF success rate as well without any distortion of the cavity. However subserous fibroids have no such negative impact on the fertility potential.  Accordingly more patient are advised to have their submucous and intramural fibroids removed before undergoing IVF or ICSI treatment.

 

The picture on the left shows 2-D view of a uterus with a posterior intramural fibroid and another one disturbing the cavity anteriorly   The picture in colour shows rendered 3-D coronal view of a uterus with right side intramural fibroid extending to the outer serosa but not reaching the cavity as shown with saline infusion sonohysterography. The patient presented with excessive menstrual bleeding which was not related to the fibroid in this case.

 

Cervical fibroids

 

This is a separate entity and could be found without the involvement of the uterine body. Anterior cervical fibroids stretch the bladder and could cause urinary symptoms where as a large posterior one could press on the rectum. 

 

Alternatively they could lead to cervical distortion with extreme displacement of the cervical canal which could interfere with sperm deposition and migration. They could also interfere with cervical dilatation and child birth.

  

Anterior and posterior cervical fibroids clamping the cervical canal. The patient needed caesarean section to deliver her baby.

---

 

Other important points

• Women with asymptomatic fibroids should not be denied low dose oral contraceptives for family planning as there is no evidence that they cause benign fibroids to grow.

• Infertile women with fibroids affecting the uterine cavity should be offered myomectomy where no other factors are identifiable.

•   Fibroids usually regress by 50% after the menopause. Accordingly rapidly growing or symptomatic fibroids in this age group should raise the suspicion of sarcomatous changes.

• HRT could cause fibroids to grow especially during the first 2 years of their use but usually cause no related symptoms. This is more so for transdermal oestrogen HRT than oral medication with oestrogens and progestogens or livial.  Accordingly patients with excessive bleeding or pain should be investigated as if they are not on HRT to exclude more sinister causes.