Adenomyosis

Endometrial-like glands and stroma within the myometrium (the uterine muscle wall) — the intramural counterpart to endometriosis, with which it frequently coexists (along with uterine fibroids). The cause is not fully understood. It is a common but under-recognised cause of heavy menstrual bleeding and secondary dysmenorrhoea.

Presentation

• Typically a parous woman in her 40s (though increasingly diagnosed in younger women now that imaging can detect it).
• Heavy menstrual bleeding with secondary dysmenorrhoea that worsens over time; bleeding is usually menstrual but can be intermenstrual. Chronic pelvic pain and dyspareunia occur.
• ~⅓ of women are asymptomatic.
• Examination: a symmetrically (globularly) enlarged, tender uterus (“boggy” uterus).
• Associated with infertility and adverse pregnancy outcomes (miscarriage, preterm birth) and significant quality-of-life impact when symptomatic.
• Symptoms resolve after menopause (oestrogen-dependent).

Diagnosis

Historically a histological diagnosis on hysterectomy specimens, but now diagnosed on imaging: transvaginal ultrasound (globular uterus, myometrial cysts, asymmetric wall thickening, an indistinct endometrial–myometrial junction) with MRI more sensitive/ specific for confirming and mapping disease. Often found alongside endometriosis and fibroids.

Management

Broadly as for endometriosis, targeting bleeding and pain:

• Medical: the 52 mg LNG-IUD is the mainstay (reduces bleeding and pain); combined hormonal contraception (extended/continuous), oral/long-acting progestogens, tranexamic acid and NSAIDs for symptom control; GnRH agonists (specialist, with add-back) for refractory disease. See Heavy menstrual bleeding & AUB for dosing.
• Procedural/surgical when medical management fails: uterine artery embolisation, endometrial ablation, or hysterectomy (the only definitive treatment).
• Refer for specialist care if fertility is desired, disease is extensive on imaging, or symptoms are refractory.

Complications

Heavy/refractory bleeding with anaemia; subfertility; and, in pregnancy, an increased risk of miscarriage and preterm birth.