Adenomyosis
Endometrial-type tissue within the muscular wall of the uterus. Often coexists with endometriosis and is frequently missed.
Adenomyosis causes heavy, painful periods and a uterus that is often tender and enlarged. It commonly occurs alongside endometriosis, which is one reason a patient can have excision surgery and still have pain afterwards if the adenomyosis was never addressed.
What it is, and what it does
Adenomyosis is the presence of endometrium-like cells inside the myometrium, the muscle of the uterus. Endometriosis is the same kind of cells outside the uterus, and the two are often found together. The studies vary on how often, but it is probably somewhere between 30 and 80 percent of the time.
Both can cause severe menstrual pain, chronic pelvic pain, pain with sex, and abnormal or very heavy bleeding, which is part of why they get mistaken for each other.
The muscle those cells sit in becomes irritated, and an irritated muscle does the one thing it knows how to do. It squeezes. That squeezing is inflammatory, and it produces severe cramping in the center of the pelvis rather than off to one side.
Why it cannot simply be cut out
One particular challenge with adenomyosis is that we cannot excise it. It is part of the uterus itself, not a growth sitting on it, so there is no plane to cut along.
Sometimes the adenomyotic cells gather into a mass within the muscle, called an adenomyoma. An adenomyoma can sometimes be excised, but it is difficult, because there is often no clear border between it and the normal muscle of the uterus.
That is the reason the treatment conversation here runs differently from endometriosis, where the disease is outside the uterus and can be removed.
What it feels like
Often a heaviness, or a sense of deep pelvic pressure, from the enlarged uterus. I have had patients whose uterus was so enlarged by adenomyosis that I could feel it on an abdominal exam.
With that comes the cramping, heavy bleeding and blood clots, sometimes clots with grayish or whitish tissue caught in them, and low back pain, because that is where the nerves from the uterus travel. Patients have described it as a hot bowling ball in the pelvis, or a spiky one, which gets the inflammation and the weight across better than a measurement does.
Not everyone has all of it, and some people have it a great deal worse than others.
Why it gets missed
Honestly, because our threshold for diagnosing it is too high. Medical students and other learners are still taught that adenomyosis can only be confirmed under a microscope, after a hysterectomy, or only called on an MRI where the junctional zone, a thin band of muscle between the lining and the wall, measures more than 12 millimeters. Neither is true.
A plain pelvic ultrasound can carry the signs: an enlarged uterus, muscle that looks patchy rather than uniform, small cysts within the muscle, a prominent back wall. On an exam, a uterus that is enlarged but not particularly firm points here rather than to fibroids. And a patient who has endometriosis has a high likelihood of adenomyosis before any scan is done.
Radiologists set a high bar before they will write the word, which is reasonable from where they sit: they are reading an image without the history. So plenty of people hold an unremarkable report while having every symptom of it.
The part I want patients to hear is that even when the uterus is a normal size and the imaging is unremarkable, clinical suspicion can be enough to treat. If nothing is offered until a scan is definitive, people simply continue to suffer.
Telling it apart from endometriosis
It can be genuinely challenging, because both cause painful periods, chronic pelvic pain, pain with sex and abnormal bleeding. What separates them is where the symptoms reach.
Adenomyosis stays central: pressure, heaviness, cramping around an enlarged uterus. Endometriosis lives on structures outside the uterus, so bladder symptoms, bowel symptoms and trouble up in the abdomen point to it. And when endometriosis involves a nerve, pain can travel to the thighs, the knees, even down to the feet. That is not typical of adenomyosis.
One timing pattern is worth knowing too. Pelvic floor muscle spasm and discomfort often begin a few days to a week before any bleeding starts, as though the adenomyosis sets the muscle off ahead of the period. When we hear that, we look hard for muscle spasm as its own problem.
What can be done short of a hysterectomy
A lot, and this question matters, because many people do not want a hysterectomy, for fertility reasons and for others.
High-dose anti-inflammatories are a reasonable start. Adenomyosis drives up inflammatory chemicals called prostaglandins inside the uterus, which is why ibuprofen and its family genuinely help, up to a real limit.
I am also a strong proponent of non-drug treatment alongside everything else. I encourage patients to pay attention to their diet and to which foods reliably worsen their symptoms, because for some people that turns out to be a lever worth having.
Hormonal treatment is the usual next step, and there are many forms: birth control pills, a hormonal IUD, the implant in the arm, high-dose progesterone, and medications that change how the body responds to estrogen. When endometriosis is present as well it can undercut these, because it makes its own estrogen, and removing the endometriosis often lets the hormonal options work better and sit easier.
For someone who needs procedural treatment but is not a safe candidate for a hysterectomy and does not want future fertility, embolization, blocking the blood supply the way we do for fibroids, is sometimes the right tool. I have used it for symptomatic adenomyosis in exactly that situation.
When a hysterectomy is the right answer
That conversation centers on your goals and values. It depends on whether you are ready for it, whether the non-surgical options are ones you want and tolerate, and where you are in your fertility journey.
Age is part of it too, and not only because of fertility. Women do reach menopause earlier after a hysterectomy, even when the ovaries stay, but the effect is modest: about two years earlier on average, which sits within the normal spread of when menopause arrives anyway. The knock-on effects on heart and bone health are correspondingly small, because the ovaries' output in those final years is already low. That is worth knowing, and it should not keep anyone living with severe pain or heavy bleeding.
The regret we see follows one pattern: someone was told a hysterectomy would fix their endometriosis symptoms, and it did not, because those symptoms were never coming from the uterus. Separating the adenomyosis symptoms from the endometriosis symptoms before anyone operates is how that is prevented.
The right time depends on what is actually causing your symptoms, what you want your life to look like afterwards, and which doors you want left open. That is a conversation, and we take the time to have it properly.