Adenomyosis
Summary
Adenomyosis is a benign gynaecological condition where endometrial glands and stroma invade the myometrium (muscular wall of the uterus). It is essentially "endometriosis of the uterine muscle." This ectopic endometrial tissue undergoes cyclical bleeding with menstruation, causing the uterus to become enlarged, boggy, and tender (the classic "bulky uterus"). The condition typically affects multiparous women in their 40s-50s and presents with heavy menstrual bleeding (menorrhagia) and painful periods (dysmenorrhea). Unlike fibroids, adenomyosis causes diffuse, symmetrical uterine enlargement. Diagnosis has shifted from histological (post-hysterectomy) to imaging-based, with MRI (Junctional Zone >12mm) being the gold standard and transvaginal ultrasound increasingly accurate. Medical management includes the Mirena IUS (first-line), hormonal therapies, and NSAIDs. Hysterectomy is the only definitive cure. Adenomyosis often coexists with fibroids and endometriosis, complicating diagnosis and management. [1,2]
Clinical Pearls
"Boggy Uterus": On bimanual examination, the uterus feels soft, tender, and diffusely enlarged (Unlike fibroids which are firm and knobbly).
"Junctional Zone >12mm": The MRI hallmark of adenomyosis. The JZ is the inner myometrial layer.
Mirena is First-Line: Levonorgestrel IUS (Mirena) thins the endometrium and reduces both bleeding and pain.
Hysterectomy is the Only Cure: Medical management is symptomatic. If family complete and symptoms severe, hysterectomy is definitive.
Demographics
| Factor | Notes |
|---|---|
| Age | Late reproductive years: 40-50 years. |
| Parity | More common in multiparous women (Have had children). |
| Prevalence | Difficult to estimate. Found in 20-35% of hysterectomy specimens. |
Risk Factors
| Risk Factor | Notes |
|---|---|
| Multiparity | Multiple pregnancies = Higher risk. |
| Prior Uterine Surgery | Caesarean section, D&C, Myomectomy – May disrupt the junctional zone. |
| Age >40 | Peak incidence in late reproductive years. |
| Early Menarche | Prolonged oestrogen exposure. |
Associated Conditions
- Endometriosis (30-40% co-occurrence).
- Uterine Fibroids (Leiomyomas).
- Endometrial Polyps.
Anatomy
- Junctional Zone (JZ): The inner third of the myometrium, immediately beneath the endometrium. Distinct on MRI.
- Normal JZ: less than 8mm.
- Adenomyosis: JZ >12mm (thickened by ectopic endometrial tissue).
Mechanism
- Endometrial Invasion: Endometrial glands and stroma invade into the myometrium (Possibly via disrupted JZ from surgery/trauma).
- Ectopic Tissue Response: Ectopic tissue responds to oestrogen/progesterone cycling.
- Cyclical Bleeding: Monthly bleeding within the myometrium causes local inflammation.
- Myometrial Hypertrophy: Reactive smooth muscle hypertrophy and oedema → Enlarged uterus.
- Pain and Bleeding: Inflammatory response causes dysmenorrhea. Enlarged vessel surface area causes menorrhagia.
Types
| Type | Description |
|---|---|
| Diffuse Adenomyosis | Scattered implants throughout the myometrium. Most common. |
| Focal Adenomyosis (Adenomyoma) | Localised nodular mass mimicking a fibroid. |
| Condition | Key Features |
|---|---|
| Adenomyosis | Diffuse/Boggy enlarged uterus, Dysmenorrhea, Menorrhagia, JZ >12mm on MRI. |
| Uterine Fibroids (Leiomyomas) | Discrete, Firm, Knobbly masses. Asymmetrical enlargement. Well-defined on imaging. |
| Endometrial Polyps | Intermenstrual bleeding. Seen on hysteroscopy/USS. |
| Endometriosis | Pelvic pain (Cyclical), Dyspareunia, Infertility. Extra-uterine disease. |
| Endometrial Cancer | Post-menopausal bleeding. Thickened endometrium on USS. Histological diagnosis. |
| Ovarian Cysts | Adnexal mass. Not uterine. USS characteristics. |
Adenomyosis vs Fibroids
| Feature | Adenomyosis | Fibroids |
|---|---|---|
| Consistency | Soft, Boggy | Firm, Hard |
| Enlargement | Diffuse, Symmetrical | Discrete masses, Asymmetrical |
| Borders | Ill-defined | Well-defined |
| USS | Heterogeneous myometrium, Cysts | Hypoechoic, Circumscribed |
| MRI | JZ thickening | Well-demarcated mass |
Symptoms
| Symptom | Notes |
|---|---|
| Menorrhagia | Heavy menstrual bleeding. Often flooding, Clots. |
| Dysmenorrhea | Severe period pain. Often described as "cramping" or "dragging". |
| Chronic Pelvic Pain | May persist beyond menstruation. |
| Dyspareunia | Deep pelvic pain during intercourse. |
| Infertility | Possible contribution (Disrupted uterine contractility/implantation). |
Examination Findings
| Finding | Notes |
|---|---|
| Bimanual Exam | Enlarged, Soft ("Boggy"), Tender uterus. Usually symmetrical (Unlike fibroids). |
| Speculum | May appear normal. |
| Size | Typically 2-3x normal size (But can be subtle). |
Imaging
| Modality | Findings | Notes |
|---|---|---|
| Transvaginal Ultrasound (TVUS) | Heterogeneous ("Rain in the forest" appearance), Asymmetrical wall thickening, Myometrial cysts, Poorly defined endomyometrial junction, Subendometrial linear striations. | Good sensitivity in experienced hands. First-line. |
| MRI Pelvis | Junctional Zone >12mm (Gold Standard finding), High signal foci on T2 (Ectopic endometrium/haemorrhage), Diffuse or focal myometrial involvement. | Most accurate. Reserved for equivocal USS or surgical planning. |
| 3D Ultrasound | Improved JZ visualisation. | Increasing use. |
Other
- Histology: Definitive diagnosis made on hysterectomy specimen (Shows endometrial glands >2.5mm from endomyometrial junction). No longer needed for diagnosis with good imaging.
Management Algorithm
SUSPECTED ADENOMYOSIS
(Heavy painful periods, Bulky tender uterus)
↓
CONFIRM DIAGNOSIS
- Transvaginal Ultrasound (First-line)
- MRI Pelvis (If USS equivocal or surgical planning)
- Exclude fibroids, polyps, cancer
↓
ASSESS PATIENT PRIORITIES
- Fertility desire?
- Severity of symptoms?
- Age and proximity to menopause?
↓
MANAGEMENT OPTIONS
┌────────────────┴────────────────┐
CONSERVATIVE INTERVENTIONAL/SURGICAL
(Non-surgical) ↓
↓
Conservative/Medical Management
| Treatment | Notes |
|---|---|
| Mirena IUS (Levonorgestrel) | First-line. Thins endometrium and adenomyotic deposits. Highly effective for bleeding and pain. 5-year licence. |
| COCP (Combined Oral Contraceptive Pill) | Suppresses ovulation. Thins endometrium. Continuous use avoids withdrawal bleeds. |
| Progestogens | Oral (Norethisterone) or Depot (Depo-Provera). Reduces bleeding. |
| Tranexamic Acid | Antifibrinolytic. Reduces bleeding on heavy days (Does not address pain). |
| NSAIDs (Mefenamic Acid) | Reduces prostaglandin-mediated pain and bleeding. |
| GnRH Agonists (Goserelin) | Induces temporary menopause. Shrinks uterus. Side effects limit long-term use. Bridge to surgery. |
Interventional Options
| Treatment | Notes |
|---|---|
| Uterine Artery Embolisation (UAE) | Radiological occlusion of uterine arteries. Variable success for adenomyosis (Less effective than for fibroids). |
| Endometrial Ablation | Caution: Adenomyosis is DEEP in the muscle. Ablation only treats surface. Risk of trapped blood ("Haematometra") if JZ is destroyed but deep disease remains. Generally AVOIDED. |
| MRI-Guided Focused Ultrasound (MRgFUS) | Thermal ablation. Experimental for adenomyosis. |
Surgical Management
| Treatment | Notes |
|---|---|
| Hysterectomy | ONLY definitive cure. Indicated if: Family complete, Severe symptoms refractory to medical management. Can be vaginal, laparoscopic, or abdominal. Ovaries usually conserved if premenopausal. |
| Excision of Adenomyoma | For focal disease in women desiring fertility. Technically challenging. Risk of uterine rupture in subsequent pregnancy. |
| Complication | Notes |
|---|---|
| Anaemia | From chronic heavy bleeding. May require iron supplementation or transfusion. |
| Reduced Quality of Life | Pain and bleeding significantly impact daily life. |
| Infertility / Subfertility | Controversial, but may impair implantation. |
| Complications of Treatment | Mirena expulsion, Surgical complications (Hysterectomy: Injury to bladder/ureter/bowel). |
| Factor | Notes |
|---|---|
| Natural History | Oestrogen-dependent. Symptoms regress after menopause. |
| Medical Management | Improves symptoms but does not cure. Symptoms often recur when treatment stops. |
| Hysterectomy | Curative. High patient satisfaction rates. |
Key Guidelines
| Guideline | Organisation | Key Recommendations |
|---|---|---|
| Heavy Menstrual Bleeding | NICE NG88 (2018) | Mirena IUS as first-line for HMB. Investigation with USS. |
| Adenomyosis | ESHRE / JMIG | MRI criteria, Management options. |
Key Points
- NICE recommends Mirena IUS as first-line for heavy menstrual bleeding regardless of cause.
- Endometrial ablation is generally contraindicated in adenomyosis.
What is Adenomyosis?
The lining of your womb (Endometrium) normally grows only on the inside surface. In adenomyosis, this lining tissue has grown INTO the muscle wall of the womb itself. Every month when you have a period, these pockets of tissue inside the muscle also bleed, causing bruising, swelling, and severe pain.
Is it cancer?
No, adenomyosis is entirely benign (Not cancerous). However, it can make life very difficult due to heavy, painful periods.
Will it affect my fertility?
It might make getting pregnant slightly harder, but many women with adenomyosis have successful pregnancies. If fertility is a concern, we can discuss this in detail.
What are the treatment options?
- Mirena Coil: A hormonal coil placed in the womb. Very effective at reducing bleeding and pain.
- Hormonal Pills: The Pill or similar medications can help control symptoms.
- Surgery: If symptoms are severe and you've completed your family, removing the womb (Hysterectomy) is the only complete cure.
Will it go away on its own?
Adenomyosis is driven by oestrogen. After menopause, when oestrogen levels drop, symptoms usually improve or resolve completely.
Primary Sources
- National Institute for Health and Care Excellence. Heavy menstrual bleeding: assessment and management (NG88). 2018. nice.org.uk/guidance/ng88
- Vannuccini S, et al. Recent advances in understanding and managing adenomyosis. F1000Res. 2017;6:283. PMID: 28408979.
Common Exam Questions
- Classic Patient: "Who typically gets adenomyosis?"
- Answer: Multiparous woman in her 40s with heavy, painful periods.
- Examination Finding: "What does the uterus feel like on examination?"
- Answer: Enlarged, Soft/Boggy, Tender, Symmetrically enlarged.
- MRI Finding: "What is the diagnostic MRI criterion?"
- Answer: Junctional Zone thickness >12mm.
- First-Line Treatment: "What is first-line medical management?"
- Answer: Mirena IUS (Levonorgestrel-releasing intrauterine system).
Viva Points
- Why Avoid Ablation?: Ablation treats the surface endometrium only. Adenomyosis is deep in the muscle. Ablation can cause trapped blood (Corneal haematometra) if the JZ is scarred but deep disease persists.
- Coexistence with Fibroids: Common. MRI helps distinguish adenomyosis from adenomyoma from fibroid.
- Difference from Fibroids: Fibroids = Discrete, Firm, Well-defined. Adenomyosis = Diffuse, Boggy, Ill-defined.
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists.