Adenomyosis

Overview – Adenomyosis

Adenomyosis is a chronic, estrogen-dependent gynaecological condition in which endometrial tissue invades the uterine muscle (myometrium), leading to painful and heavy menstrual bleeding. It is a common cause of secondary dysmenorrhoea in women of reproductive age and can significantly affect quality of life. Understanding its pathophysiology, clinical presentation, and treatment options is vital for final-year medical students preparing for both exams and real-world clinical encounters.

Definition

Adenomyosis is defined as the presence of functional endometrial glands and stroma within the myometrium, which is the smooth muscle layer of the uterus. This ectopic endometrial tissue undergoes cyclic bleeding, causing inflammation, uterine enlargement, and pain.

Aetiology

• Hyperestrogenaemia is the primary risk factor
• Associated with:
  • Multiparity
  • Increasing maternal age
  • Prior uterine surgery (e.g. caesarean section, curettage)

Pathophysiology

• Excess oestrogen → stimulates endometrial proliferation
• Invasion of endometrial glands into the myometrial layer
• Cyclical bleeding of ectopic tissue → inflammation → myometrial hypertrophy and fibrosis
• This leads to:
  • Uterine enlargement
  • Heavy menstrual bleeding (menorrhagia)
  • Severe menstrual cramps (dysmenorrhoea)

Morphology

Macroscopic Features

• Enlarged, boggy uterus
• Thickened myometrium
• Presence of haemorrhagic spots or endometrial polyps

Microscopic Features

• Endometrial glands and stroma within the myometrium
• Chronic inflammation and muscle hypertrophy
• Absence of normal boundary between endometrium and myometrium

Clinical Features

• Menorrhagia: Long and heavy periods (often >8–14 days)
• Dysmenorrhoea: Intense menstrual cramps
• Dyspareunia: Painful intercourse
• Pelvic heaviness or dragging sensation
• Symptoms may precede menstruation and worsen with age
• Often coexists with endometriosis or fibroids

Investigations

• Clinical examination: Enlarged, tender uterus
• Transvaginal ultrasound:
  • Thickened myometrium
  • Poorly defined endometrial-myometrial junction
• MRI (more sensitive):
  • Junctional zone thickening >12 mm
  • Small myometrial cysts
• Histology:
  • Required post-hysterectomy for definitive diagnosis

Management

Medical

• Progesterone-based therapy (e.g. Mirena IUD, Implanon, oral progestins)
  • Reduces bleeding and suppresses endometrial growth
• NSAIDs: Pain control
• GnRH analogues (short-term use): Hormone suppression

Surgical

• Hysterectomy: Definitive treatment for refractory or severe cases
• Conservative surgery (adenomyomectomy) may be considered if fertility preservation is required

Complications

• Infertility
• Chronic pelvic pain
• Association with endometriosis
• Rare progression to endometrial carcinoma

Differential Diagnosis

• Endometriosis
• Uterine fibroids (leiomyomas)
• Endometrial hyperplasia
• Dysfunctional uterine bleeding
• Coagulation disorders

Summary – Adenomyosis

Adenomyosis is a chronic oestrogen-driven condition characterised by the presence of endometrial tissue within the myometrium, leading to menorrhagia, dysmenorrhoea, and pelvic pain. Diagnosis relies on imaging (ultrasound or MRI), and treatment ranges from hormonal therapy to definitive hysterectomy. For broader context, see our Reproductive Health Overview page.