What is adenomyosis?

What is Adenomyosis

Adenomyosis is a benign uterine disorder where endometrial glands and stromal tissue are pathologically present within the myometrium (uterine muscle layer), causing the uterus to become enlarged and leading to symptoms such as heavy menstrual bleeding, pelvic pain, and dysmenorrhea. 1, 2

Pathophysiology

• The condition involves invasion of endometrial tissue into the myometrium, causing alterations in the junctional zone between the endometrium and myometrium 3, 2
• The pathogenesis involves sex steroid hormone abnormalities, inflammation, fibrosis, and neuroangiogenesis, though the exact mechanisms remain incompletely understood 2, 4
• Several theories explain disease development including microtrauma of the endometrial-myometrial interface, enhanced endometrial invasion, stem cell metaplasia in myometrium, and infiltration from retrograde menstrual flow 4
• The disease causes hyperplasia and hypertrophy of surrounding smooth muscle cells where endometrial tissue is abnormally located 4

Clinical Presentation

Common symptoms include:

• Heavy or prolonged menstrual bleeding that may disrupt daily activities 5, 1
• Dysmenorrhea (painful menstruation) 1, 3
• Dyspareunia (painful intercourse) 6
• Chronic pelvic pain 1, 6
• Infertility and adverse pregnancy outcomes including increased miscarriage risk and obstetric complications 1, 6

However, adenomyosis can also be completely asymptomatic in some women. 1, 3

Epidemiology and Changing Demographics

• Historically considered a condition of multiparous women over 40 years old diagnosed at hysterectomy 1
• The epidemiological scenario has completely changed with adenomyosis increasingly identified in young women of reproductive age through non-invasive imaging techniques 1, 2
• The condition often coexists with other gynecological disorders such as endometriosis and uterine fibroids, increasing diagnostic complexity 1, 2

Diagnostic Approach

• Transvaginal ultrasound is the first-line imaging modality to confirm adenomyosis 7
• MRI should be performed to better characterize disease extent when ultrasound findings are inconclusive or to exclude other pathologies 7
• An integrated non-invasive diagnostic approach considering risk factors, clinical symptoms, examination findings, and imaging is recommended for accurate identification 2
• The disease presents in different phenotypes: diffuse adenomyosis (widespread involvement) and focal adenomyosis (localized adenomyomas) 2

Important Clinical Considerations

• Adenomyosis is classified as a specific entity in the PALM-COEIN FIGO classification system for causes of abnormal uterine bleeding 1
• The condition requires lifelong management planning due to its negative impact on quality of life, fertility, and pregnancy outcomes 1
• Diagnostic criteria remain controversial with no universal agreement on definitions from both histopathological and imaging perspectives 1, 2
• While diffuse adenomyosis is straightforward histologically, limited disease has poor inter-observer reproducibility leading to extreme variations in reported prevalence 2