Is There Really a Difference Between Adenomyosis and Endometriosis?

Even though endometriosis and adenomyosis are considered distinct from one another in the medical literature and our doctors’ offices, both diseases share the same definition: the presence of endometrial-like tissue in places other than the endometrium. In the case of endo, this occurs outside the uterus, “most commonly within the lower abdomen and pelvis.”¹ In the case of adeno, it occurs “deep within the myometrium,”² the muscle of the uterus. Both are estrogen-dependent “and share many molecular aberrations,”³ as well as similar symptoms. And they often occur simultaneously. So, other than where this endometrial-like tissue shows up, is there really any difference between adenomyosis and endometriosis?

The theory of retrograde menstruation

Adenomyosis had once been referred to as “endometriosis interna,” that is, endometriosis that infiltrates internally—into the uterus. This was compared to “endometriosis externa“—endometriosis that occurs outside the uterus, or as we call it today, plain, old endometriosis. (And to add to the confusion, “deep endometriosis” is now called “adenomyosis externa.”)

Then in 1927, Sampson’s theory,⁴ commonly referred to as “reflux” or “retrograde menstruation,” came along. This was the idea that some menstrual blood flows back through the Fallopian tubes of the uterus and out into the abdominal cavity, instead of through the cervix and out the vagina. In the process, for some reason, endometrial cells get stuck in some women and turn into the lesions that define endometriosis. This theory of retrograde menstruation doesn’t apply to the uterus, because it doesn’t imply blood flowing in the wrong direction. So adenomyosis was thought to have a different cause than that of endometriosis. And from that point forward, adenomyosis and endometriosis began to be referred to as distinct diseases.⁵

However, retrograde menstruation is considered a common occurrence, “perhaps universal among menstruating women,”⁶ whereas endometriosis only occurs in ten percent of women. So Sampson’s theory doesn’t really hold water (or should I say, blood?). In 2002, Redwine also tried to refute Sampson’s theory, because he found that the tissue of endometrial lesions was not exactly the same as that of the “eutopic” endometrium.⁷ But this may be because the immune system sees the “ectopic” endometrial tissue as an invader, and being the good bodyguard that it is (or is trying to be), it creates an inflammatory environment, trying to kill it. This would explain the altered behaviors of macrophages and T-cells,⁸ as well as fibrous scar tissue seen in the lesions.

Either way, if Sampson’s retrograde menstruation theory is incorrect, why are we still differentiating the two diseases, nearly a century later?

Other theories on what causes endometriosis and adenomyosis

Neither the cause of adenomyosis, nor of endometriosis, is known for sure, but several other theories have been proposed.

Some believe that adenomyosis is caused by trauma to the womb through surgery,⁹ such as appendectomy or C-section. But a significant number of women in our Facebook group had never undergone surgery of any kind before developing adenomyosis, so this can’t always be the case. (Granted my little poll was far from scientific. But you either had surgery, or you didn’t. There isn’t much nuance here).

Another theory for the cause of endometriosis is called Mülleriosis or Müllerianosis. This is the idea that something goes awry in the womb when the embryo is undergoing cell differentiation and forming its organs. Somehow, bits of the endometrium end up in other parts of the body and are there from birth. This theory is supported by the findings of misplaced endometrial tissues in early puberty, and in rare cases, in newborns¹⁰ and even men.¹¹ But the ectopic endometrial tissue doesn’t become symptomatic until something in the hormonal environment changes. (In the case of the man with endometriosis, it was due to prolonged estrogen therapy).

Mülleriosis has been proposed as the cause of both adenomyosis and endometriosis.¹² Its not 100 percent established, but it is more plausible than the retrograde menstruation theory, so separating the two diseases due to their cause does not currently make sense.

What are the symptoms of endometriosis and adenomyosis?

Endometriosis and adenomyosis share many similar symptoms, including what the medical literature calls dysmenorrhea or “painful periods.” This makes it sound like just a few bad cramps, but we all know its way more than that. The invasion of endometrial-like tissue into the womb causes extreme knife-like cramps that adeno patients, in particular, complain of. But we know endo ladies suffer from debilitating periods, too.

Below is a chart comparing more of the symptoms between both diseases, and as you can see, the only place the two really differ is when it comes to bleeding.

Endometriosis Symptoms	Adenomyosis Symptoms
painful periods (dysmenorrhea)	painful periods (dysmenorrhea)
painful sexual intercourse (dyspareunia)	painful sexual intercourse (dyspareunia)
chronic pelvic pain	chronic pelvic pain
painful urination (dysuria)	painful urination (dysuria)
painful bowel movements (dyschezia)	painful bowel movements (dyschezia)
infertility	infertility
fatigue and/or depression, especially during your period	fatigue and/or depression, especially during your period
gastrointestinal symptoms: bloating, nausea, constipation and/or diarrhea	gastrointestinal symptoms: bloating, nausea, constipation and/or diarrhea
co-existence of adenomyosis	co-existence of endometriosis
co-existence of uterine fibroids	co-existence of uterine fibroids
anemia	anemia
	abnormal uterine bleeding (AUB)
	enlarged uterus

Most medical papers do not consider “Abnormal Uterine Bleeding” (AUB) as a symptom of endometriosis, whereas adenomyosis is well-known to cause excessive and prolonged bleeding. The reasons why they differ here are obvious and simple: because the endometrial-like tissue exists in and effects the womb in adenomyosis. It does not exist in and effect the womb in endometriosis.

But is this reason enough to distinguish between the two diseases? After all, we don’t give endometriosis a completely different name if endometrial-like tissue shows up in the rectum versus the bladder. And surely they cause complications related specifically to those body parts, too.

Another symptom that is thought to only occur in adenomyosis, is an enlarged uterus. However Benagiano and Brosens¹³ have reported that increased thickness of the uterus occurs in women with endometriosis, as well, especially in more advanced stages. This is due to a dysfunction of the endometrium in the inner myometrium, called the junctional zone (JZ), a symptom also shared with adenomyosis.

Furthermore, in case you want to get really geeky about it, they observed “a number of similarities… in functional and molecular aberrations of the eutopic endometrium in both situations.” From alterations in expression of specific genes and proteins, increased cytokine production, and more. Vannuccini et al. also point out that endometriosis and adenomyosis “share common genetic mutations and epigenetic changes in sex steroid hormone receptors and similar inflammatory mediators.”¹⁴

This is why Benagiano and Brosens proposed that the two diseases be reunified as the same disease. Given these similarities, as well as their shared symptoms, possible cause, and even their links to autoimmune disease, I agree. Isn’t it time we treated endometriosis and adenomyosis as the same disease?

Hysterectomy is not a cure for adenomyosis!

The problem with separating adenomyosis out from endometriosis is that doctors can say, “the only cure for adenomyosis is a hysterectomy.” I’ve heard this mantra so often, I no longer allow it in the group. First of all, because, while Western medicine has not yet identified an actual cure, that doesn’t mean there isn’t one.

Secondly, because a high degree of adenomyosis sufferers also have endometriosis—42.3 percent, according to a 2017 study.¹⁵ And a 2020 study found that both endometriosis and adenomyosis co-occur “in up to 80% of patients,” suggesting both diseases “may be biologically related.”¹⁶ This makes sense, because many endo sufferers know, endometriosis doesn’t always show up in just one body part.

So what if adenomyosis was just another form of endometriosis? Or what if they were both autoimmune diseases? Then nothing has been cured! Only the body part where the symptoms have shown up has been removed. We wouldn’t think of removing the vagina or the bowel if the lesions showed up there. And we would know that the endo hasn’t been “cured,” anyway. It has only been “excised.”

Due to the likelihood that adenomyosis is an autoimmune disease, the underlying causes have not been fixed and symptoms could manifest elsewhere. In fact, many women in our group have had endometriosis show up after a hysterectomy, a documented occurrence.¹⁷

This is why I keep saying, “hysterectomy is not a cure for adenomyosis!” Or as Antero et al. say with less emphasis, “hysterectomy may not be curative.”¹⁸

How to treat endometriosis and adenomyosis, naturally

Up until recently, adenomyosis has been considered a rare disease, so there is much less data available on it, compared to endometriosis. This is because it used to only be identified after hysterectomy, before more modern imaging tools became available for diagnosis.¹⁹ But because both diseases contain enough overlap in symptoms and pathophysiology, conventional medical treatment has ended up using the same hormone- and immune-modulation therapies for both diseases, interchangeably.^{20 21}

Unfortunately, far too many women with endometriosis and/or adenomyosis know, the treatments they’re getting through conventional medicine aren’t doing much to alleviate their symptoms.

Because I see adenomyosis and endometriosis as essentially the same disease, given my arguments laid out above, I believe the same alternative and natural treatments can be applied to both adenomyosis and endometriosis. These treatments may also help related disorders, such as fibroids, PCOS, and infertility as well. As I said in my last post on autoimmunity, we need to be treating the whole system.

I’ll continue to get into specifics in the coming weeks and months, but for now, please see my Top 3 Tips for Treating Endometriosis Naturally, as well as how to reverse autoimmunity naturally.

And please, don’t let anyone tell you that hysterectomy is a cure for adenomyosis!