Aednomyosis

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adenomyosis clinical overview diagnosis treatment 2025

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I now have comprehensive information from multiple authoritative textbooks. Here is a complete overview:

Adenomyosis

Definition

Adenomyosis is the presence of endometrial glands and stroma within the myometrium (uterine smooth muscle), accompanied by reactive smooth muscle hypertrophy and hyperplasia. The ectopic endometrial tissue may be diffuse (spread throughout the myometrium) or focal (forming a localized mass called an adenomyoma). It is considered the "internal" counterpart of endometriosis.

Robbins & Kumar Basic Pathology, p. 608
Robbins, Cotran & Kumar Pathologic Basis of Disease, p. 929

Epidemiology

Prevalence ranges widely (1%-70%) due to variable diagnostic criteria - historically it was only diagnosed histologically after hysterectomy
Most commonly diagnosed in the 4th and 5th decades of life
Found in 10%-88% of hysterectomy specimens
33% of cases are asymptomatic
A 2025 systematic review (PMID: 41257733) is currently the most up-to-date estimate of global prevalence

Pathogenesis

The exact mechanism is not fully established. Leading theories include:

Invagination/direct extension theory - endometrial tissue invades downward into the myometrium, possibly facilitated by disruption of the endometrial-myometrial junction
Metaplastic theory - müllerian remnants or stem cells within the myometrium undergo endometrial differentiation
Iatrogenic/trauma theory - uterine instrumentation (caesarean section, curettage, surgical termination) disrupts the endometrial-myometrial interface, allowing invasion

The ectopic tissue induces reactive myometrial hypertrophy, leading to uterine enlargement.

Risk Factors

Category	Factors
Hormonal	Early menarche (≤10 years), short cycles (≤24 days), elevated BMI, oral contraceptive use, tamoxifen, prolonged oestrogen exposure
Reproductive	Increasing parity, multiple pregnancies, spontaneous miscarriage
Iatrogenic	Caesarean section, endometrial curettage, surgical termination, endometrial ablation, leiomyomas breaching the endometrial-myometrial interface
Comorbidities	Endometriosis, endometrial hyperplasia

Bailey and Love's Short Practice of Surgery, 28th ed., p. 1604

Clinical Features

Symptoms (classic triad):

Dysmenorrhoea - often severe, worsening just before menstruation
Menorrhagia (abnormal uterine bleeding) - occurs in 40%-60% of patients; caused by increased endometrial surface area, increased gland volume, and greater vascularisation
Chronic pelvic pain / dyspareunia
Subfertility

Signs:

Enlarged, globular, tender uterus - typically symmetrically enlarged ("boggy uterus")
Uterine tenderness on palpation
Note: 33% of patients are asymptomatic

Adenomyosis is part of the PALM-COEIN classification (A = adenomyosis) used by ACOG for evaluating abnormal uterine bleeding.

Diagnosis

Transvaginal Ultrasound (TVUS)

First-line imaging; accuracy 68%-86% for diffuse adenomyosis (lower for focal disease or coexisting fibroids).

MUSA (Morphological Uterus Sonographic Assessment) criteria - at least 3 of the following features are required:

Enlarged globular uterus with asymmetric myometrial thickening
Myometrial cysts (2-6 mm subendometrial cysts, seen in ~50%) representing haemorrhagic foci
Echogenic subendometrial linear striations
Hyperechogenic islands / diffuse echogenic nodules
Fan-shaped shadowing
Irregular junctional zone
Poor definition of the endometrial-myometrial interface
"Rain shower" appearance - multiple fine areas of attenuation
Speckled colour Doppler vascularity pattern

MRI (gold standard imaging)

MRI is superior for distinguishing adenomyosis from fibroids and for pre-surgical planning.

On T2-weighted images:

Diffuse or focal thickening of the junctional zone (JZ) with low signal intensity (due to smooth muscle hyperplasia)
JZ ≥ 12 mm - predicts adenomyosis with high accuracy
JZ ≤ 8 mm - excludes adenomyosis with high accuracy
JZ 8-12 mm - indeterminate; ancillary criteria used:
- High T2 signal foci within low-signal myometrium (ectopic endometrial islands)
- High T1 signal foci = punctate haemorrhage within ectopic tissue (95% PPV for adenomyosis)
- Linear T2 striations extending from endometrium into myometrium ("finger-like projections")
Cystic adenomyosis - high T1 and intermediate-low T2 foci (extensive haemorrhagic ectopic endometrium)

MRI mimics: myometrial contractions, endometrial carcinoma, fibroids

Below are MRI images showing adenomyosis (coronal and axial T2-weighted pelvis):

MRI pelvis coronal T2 - adenomyosis showing enlarged uterus (U), bladder (B), with junctional zone thickening

MRI pelvis axial T2 - adenomyosis with enlarged uterus and junctional zone changes; R = rectum

Histology (gold standard for diagnosis)

Endometrial glands and stroma >2.5 mm below the basalis layer within the myometrium
Historically only confirmed at hysterectomy
Reactive smooth muscle hyperplasia surrounds the ectopic tissue
Grainger & Allison's Diagnostic Radiology, p. 898

Management

Treatment depends on symptom severity, age, and desire for future fertility.

Medical (conservative first-line)

Drug Class	Examples	Notes
Analgesics	NSAIDs	First-line for dysmenorrhoea
Hormonal contraceptives	Combined oral contraceptive pill	Menstrual suppression
Progestogens	Levonorgestrel IUS (Mirena - off-label), dienogest, medroxyprogesterone acetate	LNG-IUS is very effective; dienogest increasingly preferred
GnRH agonists	Leuprolide, goserelin	Induces pseudomenopause; limited to 6 months without add-back due to bone loss
GnRH antagonists	Relugolix, elagolix	Newer options; oral administration
Danazol	-	Androgenic side-effects limit use
Aromatase inhibitors	Letrozole	For refractory cases
Selective progesterone receptor modulators (SPRMs)	Ulipristal acetate	Under investigation

Radiological / Minimally Invasive

Uterine Artery Embolisation (UAE) - effective for symptom relief; complications include post-embolisation syndrome (pain, nausea, fever), haemorrhage, radiation exposure, age-related impairment of ovarian reserve
High-Intensity Focused Ultrasound (HIFU) / MR-guided Focused Ultrasound (MRgFUS) - non-invasive ablation; adverse effects include abdominal pain, skin burns, sciatic nerve injury from thermal spread, and rarely intestinal perforation

Surgical (uterus-preserving - adenomyomectomy)

For patients who desire fertility preservation:

Non-excisional techniques - thermal coagulation of diseased myometrium
Partial reduction surgeries - for diffuse adenomyosis: wedge resections, wedge-shaped uterine wall removal, modified reductive surgery, transverse H-incisions
Complete adenomyotic excision - for focal adenomyosis: double- or triple-flap method, asymmetric dissection method

Definitive Surgical Treatment

Hysterectomy - the only cure; recommended when fertility is no longer desired and medical/conservative treatment has failed
Berek & Novak's Gynecology, p. 581; Bailey and Love's, p. 1604

Relationship to Fertility

Adenomyosis is associated with subfertility and adverse obstetric outcomes. A 2024 systematic review (PMID: 39049473) found independent effects of adenomyosis on maternal, placental, fetal, and neonatal outcomes even after accounting for endometriosis and ART-related factors. Lesion type, location, and junctional zone thickness are strong predictors of fertility outcomes.

Key Distinguishing Features vs. Endometriosis

Feature	Adenomyosis	Endometriosis
Location of ectopic tissue	Within myometrium	Outside uterus
Typical age	4th-5th decade	3rd-4th decade
Uterus	Enlarged, globular	Usually normal size
Malignant transformation	Not reported	Rare (peritoneal/ovarian types)
Diagnosis	TVUS / MRI / histology	Laparoscopy / histology

Recent evidence note: A 2025 meta-analysis (PMID: 41257733) provides updated global prevalence data for both adenomyosis and endometriosis. A 2024 systematic review (PMID: 39067674) examined functional uterine contractility determinants in both conditions - relevant to understanding symptom generation and fertility impact.

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