Definition
Adenomyosis is a benign gynecological disorder in which endometrial tissue (glandular and stromal cells normally lining the uterine cavity) is found within the myometrium, the muscular wall of the uterus. This ectopic presence of endometrial tissue leads to uterine enlargement and can cause menstrual and pelvic symptoms.
Epidemiology
- Most commonly diagnosed in women aged 35–50 years, particularly those who have had prior pregnancies.
- Prevalence estimates vary; histopathologic studies of hysterectomy specimens report rates ranging from 5 % to 70 %, reflecting differences in diagnostic criteria and study populations.
- The condition is less frequently identified in younger, nulliparous women, though it can occur at any reproductive age.
Pathophysiology
- The exact mechanism is not fully understood. Proposed theories include:
- Invagination Theory – direct infiltration of the basalis layer of the endometrium into the myometrium through a disrupted junctional zone.
- De Novo Metaplasia – transformation of pluripotent Müllerian remnants or myometrial stem cells into endometrial tissue.
- Stem Cell Theory – migration of bone‑marrow–derived stem cells capable of differentiating into endometrial-type cells within the myometrium.
These processes result in ectopic endometrial glands and stroma that undergo cyclic hormonal changes, leading to local inflammation, fibrosis, and smooth‑muscle hyperplasia.
Clinical Presentation
- Menorrhagia (heavy menstrual bleeding).
- Dysmenorrhea (painful menstruation) that may be severe and refractory to standard analgesics.
- Chronic pelvic pain or pressure.
- Uterine enlargement palpable on bimanual examination; may be misinterpreted as a fibroid.
- Infertility or recurrent pregnancy loss is reported in a subset of affected women.
Diagnosis
- Clinical Assessment – history and physical examination, focusing on menstrual patterns and pelvic pain.
- Imaging
- Transvaginal ultrasound: heterogeneous myometrial echotexture, myometrial cysts, and a thickened junctional zone (>12 mm) are suggestive but not definitive.
- Magnetic Resonance Imaging (MRI): higher sensitivity; characteristic findings include a thickened junctional zone, high‑intensity foci on T2‑weighted images, and diffuse uterine enlargement.
- Histopathology – definitive diagnosis requires microscopic identification of endometrial glands and stroma within the myometrium, typically obtained from hysterectomy specimens. Endometrial biopsy alone is insufficient because sampling does not reach the myometrium.
Management
- Treatment is individualized based on symptom severity, desire for fertility preservation, and patient age. Options include:
| Treatment Category | Typical Indications | Key Points |
|---|---|---|
| Medical Therapy | Mild to moderate symptoms; desire to retain fertility | • Hormonal IUD (levonorgestrel-releasing) – reduces menstrual blood loss and pain. • Combined oral contraceptives – stabilize hormonal fluctuations. • Progestins (oral or injectable) – suppress ectopic endometrial activity. • GnRH agonists/antagonists – induce hypoestrogenic state; limited to short‑term use due to side‑effects. |
| Uterine‑Sparing Procedures | Persistent symptoms despite medication; fertility desire | • Uterine artery embolization (UAE) – reduces blood flow, may shrink adenomyotic tissue; long‑term fertility impact remains uncertain. • High‑Intensity Focused Ultrasound (HIFU) – non‑invasive ablation; data on efficacy are emerging. |
| Surgical Options | Severe, refractory symptoms; no desire for future fertility | • Hysterectomy – definitive cure; indicated when other treatments fail or when malignancy cannot be excluded. • Conservative excision (adenomyomectomy) – limited to focal adenomyosis; technically demanding and associated with higher recurrence. |
Prognosis
- Adenomyosis is benign and does not increase the risk of uterine cancer.
- Symptoms may persist or recur after conservative treatment; symptom relief is achievable in the majority of women with appropriate therapy.
- Hysterectomy provides permanent resolution but eliminates reproductive potential.
Research Directions
- Ongoing studies aim to clarify molecular pathways (e.g., estrogen‑dependent signaling, inflammatory cytokine profiles) to develop targeted pharmacologic agents.
- Comparative effectiveness research is evaluating long‑term outcomes of uterine‑sparing interventions versus hysterectomy, particularly regarding quality of life and fertility preservation.
References
- Bulun SE. Adenomyosis: Pathogenesis, diagnosis and treatment. Nat Rev Endocrinol. 2020.
- Vannuccini S, et al. Adenomyosis: Pathogenesis and treatment. J Obstet Gynaecol Res. 2021.
- Exacoustos C, et al. Imaging of adenomyosis: Ultrasound and MRI. Curr Obstet Gynecol Rep. 2022.
This entry reflects current medically peer‑reviewed knowledge up to 2024.
