The complex pathogenesis and variable presentation of adenomyosis make it one of the most difficult of the FIGO PALM-COIEN abnormal uterine bleeding group to diagnose and treat. Basic clinical parameters such as prevalence are difficult to accurately assess because histological confirmation is usually employed; however, because of the access to and accuracy and utilization of transvaginal ultrasound and other advanced imaging techniques such as MRI, noninvasive diagnosis is recognized to be highly accurate.
The clinical symptoms of pain, abnormal uterine bleeding, and subfertility are the primary presentations of adenomyosis with increasing data supporting a substantial role of this disease in reducing fecundity and interfering with assisted reproductive interventions. Treatments have been aimed at managing symptoms and improving fertility options. Management by hysterectomy is not always desired by women, and with many women having children in their fourth and even fifth decades, it is often not reasonable to consider this radical option.
Highlights
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Damage to the uterine junctional zone is a primary contributor to adenomyosis.
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Diagnosis may be reliably made by well-performed ultrasonography or MRI.
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Medical managements need to be useable for a prolonged duration, with the LNG-IUD being the best option to date.
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Conservative surgical management is feasible but requires high technical skill.
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Interventional sonography and radiological techniques are emerging and beneficial alternatives to surgery.
Introduction
Adenomyosis is a structural pathology singled out in the FIGO PALM-COIEN classification system for abnormal uterine bleeding (AUB) . Similar to endometriosis, the prevalence of adenomyosis is difficult to accurately assess because histological confirmation is necessary following its clinical consideration as a potential cause of AUB on the basis of symptoms and imaging. Opinion is divided on whether adenomyosis is actually a separate pathological entity at all because some definitions such as irregularity of the endometrial–myometrial junction (the junctional zone) are also found in asymptomatic women. The diagnosis of adenomyosis has been made with increasing frequency in the last 20 years because of access to and accuracy and utilization of transvaginal ultrasound and other advanced imaging techniques such as MRI .
The principal symptoms of adenomyosis are pain and heavy menstrual bleeding (HMB). However, even these two seemingly simple presentations are debated, with some studies suggesting that there is no relationship between HMB and adenomyosis at all , whereas others report that the disease is associated with increased menstrual blood loss in addition to dysmenorrhea . Researchers have noted that adenomyosis is often not associated with infertility, although this may be in part due to its presentation in the fourth and fifth decades when childbearing is complete ; however, with women often delaying pregnancy until this time, there is increasing evidence that there is an impact on both spontaneous and assisted pregnancy when adenomyosis is present .
This chapter will examine the etiology of adenomyosis and how it may be diagnosed in the current clinical context. Management options will also be examined and critically appraised, denoting current acceptable modes of treatment and which areas require further study.
Etiology
When a wide range of prevalence is reported in the scientific literature, it is often the case that the true facts remain unknown, and this is true for adenomyosis. The disease may occur in as few as only a few percent of women through to 70% of women, with many studies suggesting a 20–35% prevalence in histological series post hysterectomy of up to 2000 women. Prevalence becomes more difficult to ascertain when varying diagnostic criteria are used during imaging before histological assessment and the differences in pathological diagnosis from center to center and even between pathologists with respect to histology .
Risk factors for the development of adenomyosis that have been well documented include multiparity and termination of pregnancy. Increasing parity of any type and cesarean delivery are reported to increase the risk of developing adenomyosis , with a study of 594 women finding an odds ratio of 5 for this association. This association was not reported to be as strong in a larger series of 1334 women, although increasing parity did increase the histological confirmation of adenomyosis . In the California Teachers Study, 951 women with histologically confirmed adenomyosis were compared with 79,495 disease-free women, and increasing parity and longer estrogen exposure such as early menarche, short cycles, and obesity were reported as risk factors from this linkage study .
It is possible that increasing parity is more likely to breach the endometrial–myometrial junction leading to glandular elements growing within the myometrium. This same etiological hypothesis may be applied to uterine surgery where curettage , termination of pregnancy , and cesarean delivery have been associated with an increased risk of developing adenomyosis.
Not all epidemiological studies have suggested these associations, with a retrospective study of 549 women with histological adenomyosis finding no correlation between parity and previous surgery and a separate retrospective study of 873 women showing no correlation for any individual uterine procedure, although an increased correlation was observed when all of these were combined . Such variation in published data is not unique to adenomyosis and is all the more reason for consensus agreement on diagnostics and methodologically sound studies.
Other risk factors for the development of adenomyosis include the use of tamoxifen , whereas cigarette smoking may be protective , possibly because of an effect on circulating estrogen levels . Increasing age is a reliable risk factor, with increasing estrogenic exposure postulated as contributory .
The association between adenomyosis and endometriosis is hotly debated on whether they are separate entities or part of a continuum of diseases. Imaging studies certainly support a high association of adenomysosis with endometriosis , and similar pathogenetic pathways are postulated for the development of both diseases . Opposing data from a retrospective study of 594 women who underwent hysterectomy reported no increase in the association between adenomyosis and endometriosis, although the possibility of endometriosis being present and not reported or removal of this pathology exists . Other gynecological pathologies may also be associated, with a retrospective study of 959 women having polypectomy reporting a significant association between the presence of endometrial polyps and adenomyosis (p = 0.016), and this association was higher when endocervical polyps were present (p = 0.002) .
Since histological diagnosis is generally a retrospective diagnosis made after uterine extirpation, the second major factor in the variability of epidemiological discussion derives from the definition of disease. The diagnosis may only be truly made when endometrium or endometrium-like structures are present in the myometrium with smooth muscle hypertrophy or hyperplasia . This requires invasive diagnosis by extirpative surgery that may not be desired by the woman or by biopsy that may miss the actual lesions .
Although the finding of glandular and stromal tissue within the myometrium is generally agreed upon, the depth at which this occurs from the eutopic endometrium where there is no basement membrane is more problematic. Depth of penetration into the myometrium may depend on the angle of sectioning during specimen preparation and the natural irregularity of the endometrial–myometrial border . The requirement for the ectopic endometrium to be directly connected to eutopic basalis is also a variant that is fiercely debated because isolated cystic lesions deep in the myometrium are well recorded, separate from the endometrium. Table 1 reports the varying definitions of adenomyosis.
