Adenomyosis

Adenomyosis

Overview

Adenomyosis is a gynecological disorder that is characterized by the overgrowth of the endometrium into the underlying myometrium. 

Adenomyosis is an important clinical challenge in gynecology and healthcare economics. Estimates of the prevalence of adenomyosis vary widely from 5% to 70% which is probably related to inconsistencies in the histopathologic criteria for diagnosis. In the past, the diagnosis of adenomyosis was made solely based on histological analysis. An accurate determination of its incidence or prevalence has therefore not been carried out.


Historical background of Adenomyosis:

The first description of the condition initially referred to as “adenomyoma” was provided in 1860 by the German pathologist Carl von Rokitansky, who found endometrial glands in the myometrium and subsequently referred to this finding as “cystosarcoma adenoids uterinum”. The modern definition of adenomyosis was provided in 1972 by Bird who stated: “Adenomyosis may be defined as the benign invasion of endometrium into the myometrium, producing a diffusely enlarged uterus which microscopically exhibits ectopic non-neoplastic, endometrial glands and stroma surrounded by the hypertrophic and hyperplastic myometrium”. 

Although it has been recognized for over a century, reliable epidemiological studies on this condition are limited, because only postoperative diagnoses were possible in the past.

Symptoms of adenomyosis typically include menorrhagia, pelvic pain and dysmenorrhea. The precise role of adenomyosis in infertility remains controversial and whether adenomyosis per se causes infertility is unknown.


Why does diagnosing Adenomyosis become difficult through symptoms/signs  !

The difficulty in diagnosing adenomyosis clinically is due to the lack of strong positive pathognomonic signs and/or clinical findings.

  • Until recently, the diagnosis of adenomyosis was rarely established prior to hysterectomy and therefore, it is unsurprising that preoperative diagnosis rates of adenomyosis based on clinical findings are poor, ranging from 3 to 26 %. 
  • The presenting symptoms of adenomyosis are non-specific and can also be observed for disorders such as dysfunctional uterine bleeding, leiomyomas and endometriosis, among others. Thus, certain findings on the relationship between adenomyosis, menorrhagia, dysmenorrhea and pelvic pain are controversial.
  • Adenomyosis and leiomyomas commonly coexist in the same uterus, and differentiating the symptoms for each pathological process can be problematic. The incidence of concomitant adenomyosis in hysterectomy specimens of women with leiomyomas is reported to range between 15 and 57 %. 

The accurate preoperative differentiation of both conditions in the same uterus remains poor, even with the addition of imaging techniques including ultrasound and magnetic resonance imaging. 

However, research studies suggest that there are ways in which women undergoing hysterectomy with adenomyosis differ from women who have only leiomyomas. Women with adenomyosis have been shown to have lower uterine weights, more dysmenorrhea, dyspareunia, pelvic pain and more disease-specific symptoms compared to women with leiomyomas alone. Consequently, in women with symptoms that seem disproportionate to the level of leiomyoma disease, clinicians should consider the presence of adenomyosis in the differential diagnosis. Major limitations of these studies included their retrospective design which precluded an objective measurement of symptom severity. 


Establishing the Diagnosis:

Both magnetic resonance (MR) imaging and transvaginal ultrasound (TVU) are valuable in characterizing adenomyosis as they can identify myometrial cysts, distorted and heterogeneous myometrial echotexture and poorly defined foci of abnormal myometrial echotexture.

  • The most predictive TVU finding for adenomyosis is the presence of ill-defined myometrial heterogeneity. A retrospective study found the sensitivity of TVU for the diagnosis of leiomyoma up to 96.38% and the specificity up to 96.00%.
  • On magnetic resonance imaging, the junctional zone myometrium can be clearly distinguished from the endometrium and outer myometrium, and diffuse or focal thickening of this zone is now recognized as one hallmark of adenomyosis. MR imaging offers sensitivity rates of up to 88 % and specificity rates of up to 93 %.
  • Studies comparing MR and TVU offer inconclusive data, with some studies reporting equivalent results, and others report the superiority of MR imaging. 

TVU and MR imaging can be utilized in diagnosis of this condition prior to histological confirmation. Moreover, access to imaging modalities such as MRI and transvaginal ultrasound allows adequate patient counselling preoperatively in patients opting for surgical management.


Treatment for Adenomyosis:

Symptomatic women receiving treatment for adenomyosis are mostly in their fourth or fifth decade and multiparous. The diagnosis is increasingly being made in younger women who wish to maintain their fertility. Depending on the fertility requirements and the extent of adenomyosis, patients can be offered various treatment options.

Role of Medical therapy: Medical therapy of adenomyosis such as, non-steroidal anti-inflammatory drugs and/or hormonal therapy are often used for symptomatic relief and to temporarily induce regression of the adenomyosis, especially in premenopausal women and in women who wish to become pregnant.

Role of Hysterectomy: For some women with adenomyosis who have completed their family planning, hysterectomy still remains the best option and the definitive therapy.

Historically, the most common treatment for symptomatic adenomyosis has been hysterectomy. An important factor driving innovation in adenomyosis therapies is perioperative and postoperative morbidity as well as the potentially lower quality-of-life outcome associated with hysterectomy. Moreover, hysterectomy is also not appropriate in women who wish to have children.

Role of Surgical and Interventional Alternatives to Hysterectomy: The evolution of minimally invasive and uterine-conserving therapies and the demand for these therapies requires a better understanding of the disease. 

Minimally invasive surgical techniques (endometrial ablation/resection, myometrial excision/reduction, myometrial electrocoagulation, uterine artery ligation) have had limited success in the treatment of adenomyosis, and the reported data for these procedures have been obtained from case reports or small case series with only short follow-up times. Additionally, there are no evidence-based guidelines to treat adenomyosis using minimally invasive methods.

Newer techniques including uterine artery embolization (UAE) and magnetic resonance imaging guided focused ultrasound (MRgFUS) for treating adenomyosis, seem to show encouraging results in research studies. However, additional studies are required to determine the safety and efficacy of these techniques for women with adenomyosis. 

Research studies focusing on the disease-specific symptom, noninvasive diagnostic modalities as well as new surgical and interventional alternatives to hysterectomy are required for better understanding of management of women with adenomyosis. Understanding the diversity of this disease, both with regards to pathogenesis and symptomatology, may open new pathways to successful treatment as well as prevention strategies for this disease in future.