The Difference Between Endometriosis and Adenomyosis

Endometriosis is a chronic condition that has finally begun to gain some awareness in wider society and the medical community. However, its sister chronic illness, adenomyosis, remains under the radar.

Here's what you need to know about the similarities and differences between these two often debilitating conditions.

What are endometriosis and adenomyosis?

Let's start with the slightly better known of the two conditions: endometriosis. "Endo," as most sufferers refer to it, is a common gynecological condition in which tissue similar to that found in the lining of the uterus grows elsewhere. Most commonly, the tissue grows on pelvic or reproductive organs, such as the ovaries, bladder and bowels, but it can travel anywhere in the body, including the lungs and the heart, albeit this is rare.

Endometriosis affects 1 in 10 women worldwide and is the third most common gynecological condition. However, due to its complexity and the fact that its symptoms often resemble those of other conditions—such as polycystic ovary syndrome (PCOS), irritable bowel syndrome (IBS) or painful periods—it takes an average of 7.5 years to diagnose endo.

Unlike endometriosis, adenomyosis is strictly limited to the uterus and occurs when the endometrial tissue lining the uterus breaks through the muscular wall of the uterus and begins to grow there. Instead of leaving the body, as it would during a normal menstrual cycle, this displaced tissue thickens and bleeds during each menstrual cycle, leading to swelling of the uterus that causes severe discomfort, as you can imagine.

Adenomyosis is thought to affect 20 percent to 65 percent of women, however, the true percentage is hard to calculate as some adenomyosis may be asymptomatic and, therefore, never receives a diagnosis.

So, to summarize, endo is when uterine-like tissue grows outside the uterus and adeno is when uterine tissue grows through the lining of the uterus into the muscle.

Differences and similarities between the two conditions

The easiest way to differentiate between the two conditions is to imagine them as "inside versus outside," with endometriosis being a condition that occurs outside the uterus, while adenomyosis occurs solely in the uterus.

Symptoms of the conditions tend to overlap, with dysmenorrhea (painful periods), dyspareunia (painful sexual intercourse) and severe pelvic pain being the most common symptoms for both. Keeping a journal about your early symptoms can help doctors figure out which condition(s) you may have.

For example, people who have endometriosis may also feel pain during urination or bowel movements, whereas those with adenomyosis may have swelling or bloating around their uterus and abnormal bleeding during or in between periods.

That's not to say these symptoms are a clear indicator of either endometriosis or adenomyosis. They could indicate other issues, such as ovarian cysts. Therefore, most doctors order imaging tests, such as an ultrasound or MRI, or exploratory surgery before giving a clear diagnosis.

Can you have both endometriosis and adenomyosis?

Since endometriosis and adenomyosis occur in different places and have slightly different mechanisms, it is possible to have both conditions at the same time. Depending on the severity of the conditions and the symptoms, a doctor may recommend similar treatment options.

"The general first steps in treatment are the same for both, which is when we could prescribe…hormonal contraception to suppress the ovaries from making estrogen, because whether it's endometriosis or adenomyosis, they're fed by estrogen that your ovaries are making," said Cindy Duke, M.D., an OB-GYN, fertility expert and virologist at the Nevada Fertility Institute.

Hormonal treatments, such as birth control pills, may be recommended to control the menstrual cycle and prevent the growth of endometrial tissue, however, this doesn't get rid of the tissue that has already grown. Another type of hormonal treatment, known as gonadotropin-releasing hormone (GnRH) antagonist, may be suggested to prevent the ovaries from producing estrogen and progesterone, essentially causing chemical menopause.

If adenomyosis is causing excessive bleeding, medication may be recommended to reduce the bleeding and pain. If these treatments do not appear to be calming down the symptoms, the doctor may recommend a hysterectomy, or removal of the womb. However, this procedure is recommended only as a last resort and to people who don't wish to have children in the future.

A hysterectomy can also be recommended for endometriosis, although it's more likely the doctor will first suggest either an endometriosis ablation or excision surgery. Both of these surgeries are performed laparoscopically (through several tiny incisions) and only by a specialist surgeon. It's important to note that having surgery comes with the risk of further damage to organs or a buildup of scar tissue.

Doctors can analyze your situation and symptoms thoroughly before deciding what form of treatment is most beneficial.

Diagnosing adenomyosis and endometriosis

Unfortunately, as with most gynecological conditions, endometriosis and adenomyosis can be difficult to diagnose: as noted, an average of 7.5 years for endometriosis, though there are no statistics on how long it takes to diagnose adenomyosis.

"Somewhere between 10 percent to 20 percent of adenomyosis patients will be diagnosed incidentally, meaning you're sort of doing an ultrasound or you send them for an MRI and you realize that what we call the junctional zone is disappearing, which is the space where the lining is supposed to meet the muscle of the uterus," Duke explained.

"There should be a very distinct line between the two, but when that lining is now invading into the muscle, that distinct border between the cavity lining and the muscle disappears with adenomyosis, so diagnosis is hard," she said.

This delayed diagnosis often occurs because abnormal symptoms, such as heavy bleeding and painful periods, are overlooked or normalized by medical professionals. It's important to know and look out for the most common signs of both conditions: pain during menstruation, pain during intercourse and pelvic pain in general. If you're struggling with any of these symptoms, notify your general practitioner so they can assess whether you need further examination or a referral to a specialist.

It's useful to keep an eye out for other symptoms, such as pain while urinating or passing bowel movements, as this could indicate endometriosis. Similarly, if you notice bloating or swelling in your lower pelvis, you may have an enlarged uterus that could be a result of adenomyosis.

Identifying symptoms such as these could help your doctor get a more detailed picture of what's happening inside you and how to diagnose and treat it.