What is it?

Adenomyosis (pronounced ad-uh-no-my-O-sis) is a condition of the uterus or womb where the endometrial cells which normally line the uterine cavity, grow in the muscle part of the wall of the uterus.

Adeno = glands

Myo = muscle

Osis = condition

What causes it?

The cause of adenomyosis is unknown. There are a number of theories:

• The endometrial or lining cells directly invade into the muscle layer.
• The endometrium was deposited into the uterine muscle early in the foetal life before birth.
• The inflammation of the endometrium after childbirth leading to endometrial cells passing into the weakened muscle layer.

Adenomyosis is only seen in the reproductive years because its growth requires oestrogens. After the menopause, adenomyosis regresses because of the lack of oestrogen.

Who is at risk?

The known risks are:

• Previous uterine surgery such as a caesarean section or fibroid removal.
• Childbirth
• There seems to be an association with endometriosis but adenomyosis and endometriosis are separate conditions

Because of the association with childbirth or uterine surgery, it is more likely to occur in women between 30-50 years.

Incidence

The incidence is unknown with studies showing a wide range from 8-85%.

Where does it occur? What does it look like?

Adenomyosis occurs in the muscle layer of the uterus. It is most likely to be in the back wall of the uterus but can be throughout the muscle layer. Adenomyosis can also be confined to an area and can lead to a mass of adenomyosis called an adenomyoma.

The endometrial cells undergo the same changes as the lining cells of the uterus. When the period occurs these cells also bleed but because they are trapped in the muscle layer they form little pockets of old blood within the muscle.

What are the signs and symptoms?

The most common symptoms are:

• Abnormal or heavy menstrual bleeding
• Painful periods, often after years without pain
• Pain with intercourse (dyspareunia)
• Infertility (it is not known if there is an association but there is in women with endometriosis)
• Symptoms of anaemia or iron deficiency such as tiredness or dizziness because of the heavy menstrual bleeding.
• On vaginal examination, the uterus feels enlarged and is often tender to touch.

When do I seek help?

It is appropriate to seek help when your symptoms are:

• Impacting on your health
• Impacting on your ability to live your life normally without interference to home and work
• Interfering in your sexual function and relationships

How is it diagnosed?

It may be difficult to diagnose. The main test that is recommended is a transvaginal ultrasound. The test should be preferably be performed by a gynaecologist who specialises in ultrasound, as often ultrasonagraphers may be inexperienced in diagnosis of adenomyosis.

The other test which is being used more frequently now is an MRI (magnetic resonance imaging).

Adenomyosis is often only diagnosed after hysterectomy by the pathology test on the uterus that has been removed.

How is it treated?

Adenomyosis is difficult to treat.

• Hysterectomy is the only way to completely remove adenomyosis.
• The progestogen-releasing IUD (Mirena) has been used to reduce the growth and thin the endometrial cells which in turn reduces the size or volume of the uterus and therefore may reduce pain with intercourse and bleeding.
• In the presence of infertility and endometriosis, GnRH agonists may be used temporarily. These medications are used only for some months and cause a thinning of the endometrium and a reduction in the uterine size. They also suppress the period, stop ovulation and cause a temporary chemical menopause.
• If there is an adenomyoma, surgical removal (preferably via laparoscopy) may be performed.

Ultrasound techniques have been recently used to treat localized adenomyomas:

• MRI guided focused ultrasound treatment
• High intensity focused ultrasound ablation

Further resources

Websites

Mayo Clinic – Adenomyosis

Webmd – What is adenomyosis

Content updated March 3, 2011