Synonyms: endometriosis interna, uterine endometriosis, internal endometriosis
General description: Adenomyosis is the presence of endometrial glands and supporting tissues in the muscle of the uterus where it would not occur normally. When the gland tissue grows during the menstrual cycle and then at menses tries to slough, the old tissue and blood cannot escape the uterine muscle and flow out of the cervix as part of normal menses. This trapping of the blood and tissue causes uterine pain in the form of monthly menstrual cramps. It also produces abnormal uterine bleeding when some of the blood finally escapes the muscle resulting in prolonged spotting. It more often occurs in the posterior wall of the uterus.
Is it common?
The background incidence of adenomyosis in all women either with or without symptoms is not known precisely because only in recent years has MRI imaging been able to diagnose adenomyosis without doing a hysterectomy. In studies of chronic pelvic pain in which women had hysterectomies, the incidence of adenomyosis is about 15% to 25% (1, 2). It seems to be about the same incidence in hysterectomy specimens from women without pain as from women with pain so it is possible that this represents the background incidence. Differentiating features Cyclic, cramping uterine pain beginning later in reproductive life (generally after age 35) and often associated with prolonged and heavy menses is the classic presentation. It is difficult to differentiate from endometriosis if there is no abnormal bleeding and if it occurs earlier than age 40. Endometriosis tends to present earlier (20-40) and if there is abnormal bleeding it tends to be premenstrual spotting rather than heavy and prolonged nenses. The abnormal bleeding pattern of adenomyosis is similar to that found in perimenopause due to dysfunctional ovulatory problems.
On pelvic exam there may be uterine enlargement from about 6-10 weeks pregnancy size.
Patterns of adenomyosis as recognized by MRI seem to either be diffusely spread throughout the uterus (about 66%) or focal lesions (33%) that only occur in one or two places (3). On T2-weighted magnetic resonance images, diffuse adenomyosis usually appears as diffuse thickening of the endometrial-myometrial junctional zone (7-37 mm; mean, 16 mm) with homogeneous low signal intensity. Focal adenomyosis appears on both T2-weighted and contrast-enhanced T1-weighted MR images as a localized, low-signal-intensity round or oval mass with a diameter of 2-7 cm (mean, 3.8 cm) and usually has ill-defined margins.
The uterus can feel soft and boggy on pelvic exam. Sometimes adenomyosis is associated with uterine fibroids (leiomyomata) (4 ). For an in depth discussion on pre surgical ultrasound imaging and diagnosis of adenomyosis, see (The Presurgical Diagnosis of Diffuse Adenomyosis by Helen Bickerstaff, MB, BChir. Cause Cause is basically unknown although there seems to be an increased incidence associated with any child birth (5), pregnancy terminations (6), Cesarean sections 7) and and even tubal ligations (8). It would appear that any trauma to the uterus may increase the chance that endometrial tissue becomes relocated from the uterine lining. Unnecessary
studies Computerized axial tomography (CAT scans) are not sensitive enough for imaging adenomyosis.
Endometrial biopsy is not used to diagnose adenomyosis. It just picks up the surface endometrium and not pockets deep in the myometrium. It may be indicated to rule out other intrauterine causes of bleeding, however.
untreated The glandular tissue probably just becomes atrophic with scarring over after a woman goes through menopause. Estrogen replacement therapy may retard this process.
Adenomyosis may occasionally be associated with post menopausal bleeding (9).
Goals of therapy (Rx)
If the primary symptom is cyclic menstrual cramps, the therapeutic goal is to decrease or totally cure those cramps.
If abnormal bleeding is a major symptom, the goal is to restore the bleeding pattern to normal or to totally stop any menstrual or abnormal bleeding.
1st choice therapy Hysterectomy is probably over 80% effective in eliminating pain and abnormal bleeding (10, 11) if a woman has finished childbearing and is willing to undergo surgery. Gonadotropin releasing agents (e.g., Lupron ®) are the first choice for medical therapy for the pain but the problem is that the adenomyosis seems to recur after discontinuing the therapy. It can be used, however, to reduce the amount of adenomyosis and then the remaining areas can be resected if, for example, a woman wants to get pregnant (12).
For abnormal bleeding problems and desire for uterine conservation, a progesterone intrauterine contraceptive device can also be used to improve irregular bleeding (13).
Other therapies used Hysteroscopic endometrial ablation can be a treatment for adenomyosis. One study found that endometrial ablation had about the same success rate of improving heavy menstrual periods (about 60%) whether or not adenomyosis was present (14). Thus if heavy bleeding rather than menstrual cramps is the main symptom of adenomyosis, then endometrial ablation should be considered as a treatment.
Laparoscopic myometrial resection or open myometrial resection is another treatment used if the adenomyosis is focal (15).
Treatments to avoid Chronic narcotic pain medications should be avoided.
Reason for Rx choices
Hysterectomy is much more likely to provide relief from symptoms than the other therapies. If further childbearing is desired, one of the medical therapies is the procedure of choice. An MRI should be performed and if there is a diffuse pattern of adenomyosis present, a progesterone IUCD would be the best choice for about 6 months or however long before an attempt to conceive is desired. If the MRI shows one or a few focal lesions, luteinizing hormone releasing factor can be used to reduce the area of involvement and then a laparoscopic or open resection can be performed.
Hysteroscopic endometrial ablation is a good non hysterectomy choice for women with predominantly abnormal uterine bleeding and who either have high operative risks, or who are adverse to removal of the uterus.