Endometriosis and Adenomyosis: Decoding Their Contribution To Pelvic Pain
A side-by-side guide to how these conditions overlap, differ, and drive pelvic pain.
Endometriosis and Adenomyosis: Similarities, Differences, Associations, and Research
Endometriosis and adenomyosis affect millions of women worldwide. While they share certain similarities, they also differ in their pathophysiology, clinical presentation, and management. Comparing and contrasting these conditions helps clarify their overlap, distinctions, and related health associations, with relevant references noted throughout.
Similarities
Both endometriosis and adenomyosis involve the growth of endometrial-like tissue outside the uterine cavity. This ectopic tissue remains responsive to hormonal changes, leading to inflammation, pain, and other similar symptoms that can significantly interfere with quality of life (1). Both conditions predominantly affect women of reproductive age and are associated with dysmenorrhea (painful periods), dyspareunia (painful intercourse), and infertility (2). Although the exact causes are unclear, a combination of genetic, hormonal, and immune factors is thought to contribute to both (3). Either condition can also continue beyond menopause or even be present initially after menopause.
Key Differences
Anatomical location
Although both conditions involve ectopic endometrial-like tissue, they differ in anatomical location. Endometriosis is characterized by endometrial-like tissue outside the uterus, commonly on the ovaries, fallopian tubes, the peritoneum (the pelvic and abdominal skin-like lining), and other organs (4). Adenomyosis, by contrast, is defined by the invasion of endometrial-like tissue into the myometrium, the muscular wall of the uterus (5).
Prevalence
Endometriosis affects approximately 10% of women of reproductive age, whereas adenomyosis is thought to impact between 20% and 35% in this group (6). The true prevalence of both conditions may be underestimated due to the invasive nature of diagnostic procedures and non-specific symptoms (7).
Diagnosis
The gold standard for diagnosing endometriosis is surgery using laparoscopy or robotics, both minimally invasive procedures that allow direct visualization and, if necessary, excision of endometrial-like lesions (8). Adenomyosis, on the other hand, is typically suspected using imaging techniques such as transvaginal ultrasound or magnetic resonance imaging (MRI) and is usually confirmed by a pathologist when the uterus is removed (9). An accurate preoperative biopsy is very difficult; however, when adenomyosis is not diffuse throughout the myometrium, discrete adenomyomas can sometimes be removed while leaving the uterus in place.
Treatment
Both conditions are managed with a combination of medical and surgical therapies tailored to symptom severity and reproductive goals. Hormonal therapies—including oral contraceptives, progestins, and gonadotropin-releasing hormone (GnRH) agonists and antagonists—are commonly used to manage symptoms in both endometriosis and adenomyosis (10). Integrative measures, including anti-inflammatory and anti-oxidant hormone-modulating nutrition and lifestyle modifications, can help control symptoms and may contribute to treating root causes. Surgical approaches differ by condition. In endometriosis, the preferred intervention is laparoscopic or robotic excision of ectopic tissue (11). For adenomyosis, hysterectomy (removal of the uterus) may be considered in severe cases when fertility preservation is not a concern (12). In selected cases where imaging identifies discrete adenomyomas, removal while preserving the uterus is possible; the decision to remove the uterus is highly individualized.
Coexistence and Associated Conditions
Endometriosis and adenomyosis can coexist in the same patient, and one study found that adenomyosis is significantly more prevalent among women with endometriosis (13). Coexistence may exacerbate symptoms and complicate both diagnosis and management (14). These conditions are also linked to other health issues. Women with either may experience chronic pelvic pain that can be debilitating and significantly impact daily life (15). Adenomyosis and uterine fibroids (leiomyomas) may occur together, which can further complicate diagnosis and treatment despite being distinct entities (16). Women with endometriosis have an increased risk of autoimmune and inflammatory disorders—such as rheumatoid arthritis, systemic lupus erythematosus, and inflammatory bowel disease—while similar associations with adenomyosis are less well-established but have been suggested in some studies (17, 18). Mental health concerns, including depression, anxiety, and decreased quality of life due to chronic pain and infertility, are linked to both conditions (19).
Research and Future Directions
There is a growing body of research targeting the pathophysiology, diagnosis, and treatment of endometriosis and adenomyosis. Key areas include the identification of specific biomarkers to improve diagnostic accuracy and enable earlier intervention (20), advances in non-invasive imaging techniques to reduce reliance on invasive diagnostic procedures (21), exploration of novel therapeutic approaches such as targeted hormonal therapies, immunomodulators, and anti-inflammatory agents to improve symptom control and fertility outcomes (22), and investigation of genetic and epigenetic factors that drive development and progression to inform future treatment strategies (23).
References
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Parazzini F, Esposito G, Tozzi L, Noli S, Bianchi S. (2017). Epidemiology of endometriosis and its comorbidities. Eur J Obstet Gynecol Reprod Biol. 209: 3-7.
Zondervan KT, Becker CM, Koga K, Missmer SA, Taylor RN, Viganò P. (2018). Endometriosis. Nat Rev Dis Primers. 4(1): 9.
Giudice LC, Kao LC. (2004). Endometriosis. Lancet. 364(9447): 1789-99.
Vannuccini S, Tosti C, Carmona F, Huang SJ, Chapron C, Guo SW, Petraglia F. (2017). Pathogenesis of adenomyosis: an update on molecular mechanisms. Reprod Biomed Online. 35(5): 592-601.
Garcia L, Isaacson K. (2011). Adenomyosis: review of the literature. J Minim Invasive Gynecol. 18(4): 428-37.
Chapron C, Marcellin L, Borghese B, Santulli P. (2019). Rethinking mechanisms, diagnosis and management of endometriosis. Nat Rev Endocrinol. 15(11): 666-82.
Johnson NP, Hummelshoj L, Adamson GD, Keckstein J, Taylor HS, Abrao MS, et al. (2017). World Endometriosis Society consensus on the classification of endometriosis. Hum Reprod. 32(2): 315-24.
Champaneria R, Abedin P, Daniels J, Balogun M, Khan KS. (2010). Ultrasound scan and magnetic resonance imaging for the diagnosis of adenomyosis: systematic review comparing test accuracy. Acta Obstet Gynecol Scand. 89(11): 1374-84.
Vercellini P, Buggio L, Berlanda N, Barbara G, Somigliana E, Bosari S. (2016). Estrogen-progestins and progestins for the management of endometriosis. Fertil Steril. 106(7): 1552-71.e2.
Yeung P Jr, Sinervo K, Winer W, Albee RB Jr. (2011). Complete laparoscopic excision of endometriosis in teenagers: is postoperative hormonal suppression necessary? Fertil Steril. 95(6): 1909-12, 1912.e1.
García-Solares J, Donnez J, Donnez O, Dolmans MM. (2018). Pathogenesis of uterine adenomyosis: invagination or metaplasia? Fertil Steril. 109(3): 371-9.
Mijatovic V, Florijn E, Halim N, Schats R, Hompes P. (2010). Adenomyosis has no adverse effects on IVF/ICSI outcomes in women with endometriosis treated with long-term pituitary down-regulation before IVF/ICSI. Eur J Obstet Gynecol Reprod Biol. 151(1): 62-7.
Pinzauti S, Lazzeri L, Tosti C, Centini G, Orlandini C, Luisi S, et al. (2015). Coexistence of endometriosis and adenomyosis in women with chronic pelvic pain. J Obstet Gynaecol Res. 41(6): 909-14.
Howard FM. (2003). Chronic pelvic pain. Obstet Gynecol. 101(3): 594-611.
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Sinaii N, Cleary SD, Ballweg ML, Nieman LK, Stratton P. (2002). High rates of autoimmune and endocrine disorders, fibromyalgia, chronic fatigue syndrome and atopic diseases among women with endometriosis: a survey analysis. Hum Reprod. 17(10): 2715-24.
Benagiano G, Brosens I, Habiba M. (2015). Structural and molecular features of the endomyometrium in endometriosis and adenomyosis. Hum Reprod Update. 21(4): 445-58.
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Nisenblat V, Bossuyt PM, Shaikh R, Farquhar C, Jordan V, Scheffers CS, et al. (2016). Blood biomarkers for the non-invasive diagnosis of endometriosis. Cochrane Database Syst Rev. 5: CD012179.
Brosens I, Gordts S, Campo R, Benagiano G. (2016). Non-invasive methods of diagnosis of endometriosis. Curr Opin Obstet Gynecol. 28(4): 267-76.
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Zondervan KT, Rahmioglu N, Morris AP, Nyholt DR, Montgomery GW, Becker CM, et al. (2016). Beyond endometriosis genome-wide association study: from genomics to phenomics to the patient. Semin Reprod Med. 34(4): 242-54.