Adenomyosis - An Internal Uterine Endometriosis
Frederick R. Jelovsek MD
"I am 46 and every month before I start my period, I have really painful cramps. They are so painful that I can barely function. What could be the cause of this?" Carolyn
The new occurrence of cyclic menstrual pain in the decade of the 40's could be due to endometriosis, uterine fibroids, partial cervical stenosis or adenomyosis. By far the most likely cause of these painful menstrual cramps at this time is adenomyosis. This is sometimes called endometriosis interna or internal endometriosis.
Since this is the most likely problem that your doctor will want to rule in or rule out with diagnositic tests, let us focus on adenomyosis.
What is adenomyosis?
Adenomyosis is defined as the presence of endometrial glands and supporting tissues in the muscle of the uterus where it normally would not occur. When that gland tissue undergoes growth during the menstrual cycle and then subsequent sloughing, the old tissue and blood cannot get out of the 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 menstrual cramps. It also produces abnormal uterine bleeding as some of the blood finally escapes the muscle and results in prolonged spotting. For a picture of what adenomyosis schematically looks like, see the (images) at one gynecologist's site.
Adenomyosis occurs more often in the decade of the 40's, perimenopausally. In hysterectomy specimens, adenomyosis can be found from 15% to 25% of the time (1, 2). The glandular change of the endometrial cells in adenomyosis are often incomplete in the second half of the menstrual cycle (luteal phase) and as a result, adenomyosis may not be very responsive to suppression by progesterone.
About 50% of adenomyosis is asymptomatic although as it goes deeper into the uterine muscle it tends to be more likely to produce symptoms (3, 4). It is also often associated with fibroids (5 and often associated with other conditions such as ovarian cysts, prolapse and even gynecological cancers (6) that can cause pelvic pain.
How is adenomyosis diagnosed?
Up until recent years it was said that adenomyosis was only diagnosable by the pathologist looking at a hysterectomy specimen. Now magnetic resonance imaging (MRI) can more accurately diagnose adenomyosis although many physicians feel this is too expensive a test to use routinely.
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 (7). If a non hysterectomy treatment is being considered for adenomyosis, then MRI should be used for the diagnosis and if focal disease were shown, then surgical resection of the endometriosis without doing a hysterectomy could be considered.
Ultrasound especially using color flow doppler can also be used to diagnose adenomyosis (8) . Sometimes it has difficulty differentiating smaller fibroids (leiomyomas) from adenomyosis but it is able to pick up about 80% of the existing lesions.
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.
Hysteroscopy and needle biopsies of the uterus have also been used to diagnose adenomyosis (9), but they do not seem to be practical in a clinical sense because they miss so many areas of the uterine muscle where endometrial glands can be found.
When used in conjunction with ultrasound, they may be able to pick up areas that are positive (10). The most important concept in diagnosis is to keep in mind that since adenomyosis produces symptoms of pain and/or abnormal bleeding only 50% of the time (11), just because an imaging study finds evidence of adenomyosis, does not mean that that focus is causing the pain.
It may be that adenomyosis is a physiologic condition found in women having pelvic pain but not necessarily the total cause of the pain (12).
Does Cesarean section or tubal ligation cause adenomyosis?
There is some evidence that women who have had Cesarean sections may be at slightly higher risk (about 2 to 1) for adenomyosis 13). The theoretical basis for this would be that when a surgical incision is made into the uterus, this may allow endometrium to be seeded down into the muscle of the uterus.
This is known to occur in the abdominal incisions with Cesarean sections in that endometriosis is occasionally reported in those incisions and has to be excised (14).
Another factor that has been suggested as a possible associated factor in causing adenomyosis is tubal ligation. Under this theory, normal retrograde flow of endometrial cells in those women destined to develop endometriosis is blocked due to the ligation of the faloppian tubes.
This would increase the intrauterine pressure and force some of those cells down into the muscle of the uterus and therefore development of adenomyosis. There is some support for the concept that women who have adenomyosis have more frequently had a tubal ligation (15).
In one study, there also was a higher incidence of adenomyosis in woman who had pregnancy terminations (16). Presumably, most of these were performed by suction D&C, so again we have the concept of instrumentation of the uterus may result in endometrium that grows deeply into the muscle.
It is important to remember that having any pregnancy is also considered a risk factor (17).
What are non hysterectomy treatments for adenomyosis?
Gonadotropin releasing agents (e.g., Lupron ®) can be used to treat adenomyosis 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 (18).
A progesterone intrauterine contraceptive device can also be used to improve irregular bleeding and avoid hysterectomy (19).
The question comes up as to whether endometrial ablation might be a treatment for adenomyosis or perhaps could it even make it worse? This was looked at in one study and they found that endometrial ablation had about the same success rate of improving heavy menstrual periods (about 60%) whether or not adenomyosis was present (20).
Thus if heavy bleeding rather than menstrual cramps is the main symptom of adenomyosis, then endometrial ablation should be considered as a treatment.
Hysteroscopic endometrial ablation can sometimes remove superficial adenomyosis but in order to remove most focal adenomyosis areas that are deeper, either laparoscopic myometrial resection or open myometrial resection is needed to get rid of symptoms (21).
Is hysterectomy a very successful treatment for adenomyosis?
One would think that hysterectomy would cure the pain in 100% of women with adenomyosis undergoing this surgery, but in truth, studies have not looked specifically at the pain cure rate for women with adenomyosis undergoing hysterectomy. Overall, when pelvic pain is considered to be uterine in origin, hysterectomy significantly improves pain in 75-80% of the cases (22, 23).
Conservative surgery for adenomyosis is about 50% effective (24), so it is still likely that hysterectomy is more successful in treating it even though we do not know for sure what the success rate of hysterectomy is. It is probably that hysterectomy is at least 80% or more effective.
For all types of chronic pelvic pain, non surgical therapy can have good cure rate although not as high as hysterectomy (25).
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