Adenomyosis

Adenomyosis was once historically referred to as endometriosis interna, but it is now fully recognized as a distinct condition, albeit one with significant overlap with endometriosis.

A uterine-based disease, adenomyosis is characterized by endometrial-type glands and stroma found within the myometrium - the medical term for the muscular portion of the uterine wall - often accompanied by surrounding smooth muscle hyperplasia, fibrosis, and enlargement of the uterus (Bertucci et al., 2026; Kobayashi, 2026). Once mistakenly believed to be a condition limited only to older patients, the disease is increasingly being recognized across a broader age spectrum and can certainly occur in adolescents, such as in the case of a 17 year old whose MRI and pathology confirmed focal adenomyosis after it initially mimicked fibroids (Banović et al., 2026). Imaging-based and fertility clinic studies further suggest that adenomyosis is common among younger reproductive-age individuals, especially those presenting with infertility and pelvic pain (Tokhunts et al., 2026; Bertucci et al., 2026).

Some people who live with adenomyosis remain asymptomatic, but most experience a wide range of symptoms including heavy menstrual bleeding, severe dysmenorrhea and debilitating uterine cramping, chronic pelvic pain, infertility, and significantly reduced quality of life (Bertucci et al., 2026; Kobayashi, 2026). Additional symptoms like dyspareunia, bowel and bladder dysfunction, leg pain, urinary frequency, rectal pain, leg pain, abdominal bloating and pressure, and many others are also frequently reported by those with the condition. On imaging or at surgery, the uterus may appear swollen, ‘boggy’ or inflamed, and tender. The cost and quality of life burden of adenomyosis to the individual and the health care system alike is quite high, and incidence rates are disproportionately high among Black patients (Yu et al., 2020).

Prevalence estimates vary widely depending on population and diagnostic method. One retrospective review, for example, reported rates ranging from 1% to 70%, reflecting differences in diagnostic criteria and study populations (Matalliotakis et al., 2025). Among hysterectomy specimens, adenomyosis was identified histologically in 34.7% of cases in one cohort (La Torre et al., 2026), and in 40.7% of specimens following total Laparoscopic hysterectomy for benign disease in another (Kahveci & Kizildemir, 2026). While these numbers may over-represent more symptomatic populations, they do underscore that adenomyosis is both common and frequently underdiagnosed prior to surgery.

In 1908, an investigator named T. S. Cullen concluded that adenomyosis was an evolving invagination of the surface epithelium. That means he thought it was an ingrowth of endometrium from the inside of the uterus. Today, the exact cause still remains unclear, but current evidence supports a multifactorial process involving displacement/invasion of endometrial-type tissue into the myometrium, estrogen dependence, progesterone resistance, inflammation, fibrosis, and likely clonal or molecular alterations (Kobayashi, 2026; Egashira et al., 2026).

Preliminary diagnosis is commonly achieved via imaging modalities. Transvaginal ultrasound is typically first-line due to its accessibility, while magnetic resonance imaging can provide more detailed assessments of lesion subtype and junctional zone changes. Imaging results can lend towards diagnosis as well as assist with treatment planning (Bertucci et al., 2026; Tokhunts et al., 2026; Kobayashi, 2026). Despite advances, however, diagnosis still remains challenging, as imaging is highly operator-dependent and can be confounded by uterine positioning, anatomical variation, technical artifacts and more (Tokhunts et al., 2026).

For these reasons and more, diagnostic delay remains a major issue. In a large French e-cohort of 6,949 individuals with self-reported endometriosis and/or adenomyosis, for example, the average diagnostic delay for adenomyosis was 11 years (Breton et al., 2026). Longer delays were unsurprisingly associated with reduced access to care, greater comorbidity burden, family history of disease or chronic pelvic pain, severe dysmenorrhea, and the need to consult multiple healthcare providers before diagnosis. Adenomyosis is therefore not only difficult to diagnose - but diagnosis is frequently delayed and fraught by inequitable healthcare disparities.

Beyond pain, bleeding and other common symptoms, adenomyosis has important reproductive implications as well. It is associated with infertility, recurrent pregnancy loss, miscarriage, preterm labor, uterine atony, and other obstetric complications, although the magnitude of risk varies (Bertucci et al., 2026). Notably, adenomyosis has been linked to “unexplained infertility” and reported in 38.2% of cases of recurrent pregnancy loss, emphasizing the importance of preconception and pregnancy counseling (Bertucci et al., 2026).

The disease also frequently coexists with other conditions, particularly gynepathologies like fibroids, endometrial disorders, and ovarian cysts (Matalliotakis et al., 2025; Wang X et al., 2026). Coexistence with endometriosis is especially common. In one study of newly diagnosed endometriosis patients, for example, 38.7% had coexisting adenomyosis (Vannuccini et al., 2026).

One main reason that adenomyosis remains difficult to manage is that it is not a uniform disease. Lesions may be focal or diffuse, vary by uterine location, and differ in reproductive consequences and responsiveness to therapy, making “one-size-fits-all” treatment approaches ineffective (Kobayashi, 2026). As a result, there is no single optimal treatment for adenomyosis. Management depends on symptom profile, disease extent, lesion subtype, uterine size, patient age, and outcome goals (Kobayashi, 2026). First-line treatments typically involve hormonal therapies, including progestin-based approaches such as the levonorgestrel-releasing intrauterine system. Other uterine-sparing options like high-intensity focused ultrasound, microwave ablation, and endometrial ablation (not the same procedure as ablation of endometriosis) may reduce symptoms for some individuals like pain and heavy bleeding, but they are not curative and carry a risk of recurrence (Kobayashi, 2026; Sun et al., 2026; Wang S et al., 2026; Han et al., 2026). Hysterectomy remains the only definitive cure, though it is not appropriate for every patient. Lifestyle interventions are also sometimes used by patients but remain under-studied. A 2026 scoping review found potential benefits from dietary modification, physical activity, mindfulness, yoga, digital health interventions, and TENS, for example, but evidence specific to adenomyosis remains limited (Hough et al., 2026).

Adenomyosis is increasingly recognized as a complex, systemic condition rather than simply just a localized uterine disorder. The disease contributes to chronic pain, infertility, obstetric complications, bowel/bladder pain and dysfunction, reduced quality of life and much more, while remaining underdiagnosed for many patients for years (Bertucci et al., 2026; Breton et al., 2026) due largely to variations in imaging skills and interpretation, symptom overlap, and structural variation, as well as broader inequities in access to care (Tokhunts et al., 2026; Humphries et al., 2026; Breton et al., 2026). The field is evolving toward a more nuanced understanding of the disease, however, better recognizing its biological complexity, overlap with endometriosis and other conditions, reproductive significance, and real-world disparities that affect who is diagnosed and treated effectively (Guo, 2026; La Torre et al., 2026; Humphries et al., 2026).

Improving awareness and access to specialized care remains essential to ensuring patients receive appropriate, effective treatment for adenomyosis. If you are experiencing symptoms, we encourage you to reach out to the Center to learn more about options and how our surgeons may be able to help.
 

Citations

Banović M, Gržan D, Banović V. Focal adenomyosis in a 17-year-old patient: A case report. J Pediatr Adolesc Gynecol. 2026;39(1):135-136.

Bertucci E, Ceffa S, Danieli A, et al. Ultrasound signs of adenomyosis in pregnancy and counselling related to infertility and obstetric outcomes. Minerva Obstet Gynecol. Published online March 20, 2026. doi:10.23736/S2724-606X.25.05857-9

Breton Z, Gouesbet S, Indersie E, et al. Endometriosis diagnostic delay and its correlates: Results from the ComPaRe-Endometriosis cohort. J Womens Health (Larchmt). 2026;35(2):172-188.

Egashira H, Ishida H, Takashima A. Adenocarcinoma arising in adenomyosis: A narrative review of disease concept, molecular pathogenesis, and clinical challenges. Cureus. 2026;18(2):e104162.

Guo SW. Cracking the enigma of adenomyosis: Prospects and challenges. Nat Rev Endocrinol. 2026;22(2):74-75.

Han K, Kim MD, Kwon JH, et al. Uterine artery embolization for pure adenomyosis: Predictive factors affecting outcomes. J Vasc Interv Radiol. Published online February 27, 2026. doi:10.1016/j.jvir.2026.108682

Hough B, Drever N, Manger S. What is the evidence on lifestyle interventions for the symptom management of pelvic pain in women with endometriosis or adenomyosis? A scoping review. Am J Lifestyle Med. Published online February 24, 2026. doi:10.1177/15598276261419770

Humphries LA, Rush MA, Pollie M, et al. Diagnostic disparities in endometriosis and adenomyosis: Investigating social vulnerability and access to care in an ancestrally diverse population. J Minim Invasive Gynecol. Published online February 8, 2026. doi:10.1016/j.jmig.2026.02.010

Kahveci B, Kizildemir YZ. The impact of histopathologically proven adenomyosis on surgical outcomes and total laparoscopic hysterectomy complication rates, types, and severity. BMC Womens Health. 2026;26(1):177. doi:10.1186/s12905-026-04402-5

Kobayashi H. Treatment selection for adenomyosis based on imaging findings and patient characteristics. Int J Gynaecol Obstet. Published online March 27, 2026. doi:10.1002/ijgo.70992

La Torre F, Hurni Y, Farsi E, et al. Adenomyosis is associated with proliferative endometrial disorders. F S Sci. Published online March 6, 2026. doi:10.1016/j.xfss.2026.03.001

Matalliotakis M, Tsakiridis I, Matalliotaki C, et al. Coexistence of gynecological pathology with endometriosis and adenomyosis. Mol Clin Oncol. 2025;24(2):12.

Sun F, Qi Y, Zhuang L, Huang Y. Thermal ablation and thermal ablation combined with medical therapy for adenomyosis: A systematic review and network meta-analysis. Ultrasound Med Biol. Published online March 12, 2026. doi:10.1016/j.ultrasmedbio.2026.02.010

Tokhunts K, Mazmanyan I, Chopikyan A, et al. Ultrasound features of adenomyosis and diagnostic challenges. J Ultrasound. Published online March 13, 2026. doi:10.1007/s40477-026-01132-0

Vannuccini S, La Torre F, Gallucci E, et al. Multidimensional factors increase menstrual distress in patients with endometriosis. Eur J Obstet Gynecol Reprod Biol. 2026;318:114950.

Wang S, Huang H, Cheng M, Fang F, Lv X, Lu C. Long-term efficacy of uterine artery embolization for adenomyosis and analysis of prognostic factors: A cohort study. BMC Womens Health. Published online March 16, 2026. doi:10.1186/s12905-026-04396-0

Wang X, Fu Y, Zhao R, Liu Y, Zhao R. Classification of patients with adenomyosis based on clusters of coexisting diseases: An illustration of clinical diversity. Eur J Obstet Gynecol Reprod Biol. 2026;318:114962.

Yu et al. Adenomyosis incidence, prevalence and treatment: United States population-based study 2006-2015. Am J Obstet Gynecol. 2020 Jul;223(1):94.e1-94.e10.

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