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Adenomyosis vs Endometriosis: What’s the Difference?

Adenomyosis and endometriosis are at first sight very similar but different conditions. We’ve collected the most popular questions about these issues and addressed them to Christian Becker – Associate Professor and Co-Director of the Oxford Endometriosis CaRe Centre.

What do adenomyosis and endometriosis have in common and what are the main differences between them?

In the old days, people thought that adenomyosis is some form of endometriosis and vice versa. In fact, particularly deep endometriosis is sometimes still described as adenomyosis externa.

At the moment we know very little about endometriosis, but we know even less about adenomyosis because it's even more difficult to get to. I mean it's a diagnosis made by imaging, with ultrasound or MRI. And if you find it, you usually treat it with the Mirena coil or an oral contraceptive pill

Adenomyosis is more difficult to grasp, because with endometriosis, at least when you do a laparoscopy you can really show it (or rule it out).

There are some unspecific signs for adenomyosis during laparoscopy, but less obvious than endometriotic lesions. Although ultrasound and MRI detection nowadays are very good, the only time to really prove it is under the microscope usually after a hysterectomy.

What's the main difference? I think they are two different conditions with similar symptoms. Adenomyosis is the presence of endometrium outside of the uterine cavity but still contained within the womb whereas endometriosis is defined as the presence of this tissue outside the womb. 

While the cause of adenomyosis is entirely unclear, many experts believe that many cases endometriosis results from implantation of endometrial cells from menstrual blood which not only leaves the body through the vagina but also flows upwards through the Fallopian tubes into the abdomen. 

While the cause of adenomyosis is entirely unclear, many experts believe that many cases endometriosis results from implantation of endometrial cells from menstrual blood which not only leaves the body through the vagina but also flows upwards through the Fallopian tubes into the abdomen.

However, even that is very theoretical and I haven't seen any models which fully support this. So, I think it's a very difficult question to answer because we don't know enough about adenomyosis to really say it.

Is it actually important to tell the difference? Will treatment or forecasts differ for these two diseases?

Most doctors here would suggest the Mirena coil to women with adenomyosis, secondly the contraceptive pill.

If you have pelvic pain and heavy or irregular periods and there is no sign of adenomyosis on ultrasound and/or MRI, then probably, most doctors would try the pill first rather than a coil. 

Therefore, if you knew someone had adenomyosis, maybe that would shift you to the coil as the first-line treatment. 

Most doctors here would suggest the Mirena coil to women with adenomyosis, secondly the contraceptive pill.

But you could argue, both of these treatments work and, therefore, it doesn't really matter so much. 

It may matter from a fertility aspect because there is increasing data that adenomyosis also has an impact on implantation and fertility. Maybe from that perspective, it would help to distinguish. But the problem is, once you know it, what do you do? Hormonal therapy is not the right approach in either situation if someone is trying to conceive due to its contraceptive nature.

So, I don't think it makes much of a difference. 

Obviously, women want to know and they have the right to know, but I think technically, from a medical perspective, it's probably not going to change it very much apart from maybe shifting more towards the coil. 

On the other hand, if women are older and if they had children or if they don't want to have children, and you find adenomyosis, you may be more likely to discuss with them the option of having a hysterectomy in more detail. 

Whereas if adenomyosis is not suspected and women suffer from these symptoms, it is more likely that endometriosis is the underlying issue, and then it is questionable whether a hysterectomy will improve the pain? Yes, obviously the periods would cease but not necessarily the pain symptoms. Therefore, one would have to have a very detailed discussion about the pros and cons of the procedure and manage expectations of the patient.

What are the technologies to diagnose both of the conditions? 

With good ultrasound scan, experienced sonographers and radiologists, I think nowadays we're getting better at identifying not only adenomyosis but also signs of endometriosis. 

I think it's clear that you can identify ovarian cysts very easily. But I think we're getting much better at identifying deep endometriosis with ultrasound as well. 

Non-invasive means of detecting or ruling out endometriosis are still urgently needed particularly as there are approximately 190 million women affected by the disease worldwide.

Also, deep endometriosis nodules, not only because you can see it better, but for once the training is better for the people doing it. Plus the machines have better sensitivity now or better specificity in this case.  

Overall, superficial peritoneal endometriosis cannot be sufficiently detected nor ruled out with current imaging modalities. However, in women with scarring which could be a result of peritoneal disease, transvaginal ultrasound scans can identify signs of organs such as uterus, ovaries, bladder, and bowel being stuck together. However, adhesions can also be the result of other conditions or previous surgery.

And of course, we still have laparoscopies which are still considered the gold standard for the identification of endometriosis. However, they are invasive procedures associated with some risks to the patient. Therefore, non-invasive means of detecting or ruling out endometriosis are still urgently needed particularly as there are approximately 190 million women affected by the disease worldwide.

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