What is adenomyosis?

Written by: Lisa Gilet

Adenomyosis In Flesh and Bone

Let's talk a little about the uterus and its anatomy

Intrinsic anatomy of the uterus

The uterus, a central organ of the female reproductive system, is located in the center of the pelvis, nestled between the bladder and the rectum. Imagine a sweet fruit, almost like an upside-down pear, resting there, ready to welcome life. In fact, for women who have never had children, the size of the uterus is similar to that of this pear. But, like any fruit that ripens over time, the uterus can also grow, especially after having experienced the beauty of motherhood.

The parts of the uterus

  • Body of the uterus: This is the major and most voluminous part. Think of it as the juicy body of the pear.

  • Fundus of the uterus: This is the upper part, where the fallopian tubes connect, similar to the top of the pear near the stem.
  • Isthmus: This is the transition zone, much like the middle of the pear where it begins to narrow.
  • Cervix: This is the lower, narrower part that projects into the vagina. Think of it as the narrow base of the pear.
Anatomy of the uterus

Histology of the uterus

The uterus is not just a simple fruit; it is composed of complex layers that each have a unique function.

  • Perimetrium: The outer layer, similar to the thin skin of a fruit, which protects the rest of the structures.
  • Myometrium: This is the robust muscular layer, a bit like the firm flesh of a fruit. During childbirth, this layer contracts to help birth the baby.
  • Endometrium: The soft and nutritive inner layer, like the sweetest and juiciest part of a fruit. This is where the embryo implants and grows. This layer transforms and evolves according to menstrual cycles, ready to welcome life or renew itself.
Anatomy and histology of the uterus

The uterus is also endowed with a rich network of blood vessels, essential for nourishing the growing embryo and supporting menstrual functions.

Anatomical pathology of the uterus: adenomyosis

Adenomyosis, what is it?

Adenomyosis is an abnormality of the junctional zone between the endometrium and the myometrium of the uterus. This allows endometrial cells to pass through and infiltrate the myometrium.

It is often categorized as the little sister of endometriosis since it is a version of it localized to the uterus. However, it should be noted that a woman can have both conditions concurrently.

Adenomyosis is a silent but painful companion for many. It hides behind the walls of the uterus, where tissues similar to those of the endometrium take root where they shouldn't. This often leads to a feeling of heaviness, pain, and more intense periods.

Adenomyosis is characterized by the presence of endometrial tissue—which normally lines the inside of the uterus—in the uterine muscle layer (myometrium). This infiltration leads to hypertrophy of the myometrium and symptoms that are often painful.

Anatomopathologically, we observe:

  • Islands of glandular and stromal endometrial tissue surrounded by hypertrophied smooth muscles.
  • Reactive hyperplasia of the adjacent myometrium.
  • Internal microhemorrhages and fibrosis that can contribute to an increase in the size of the uterus.
Anatomy of adenomyosis

What are the symptoms of adenomyosis?

This pathology is asymptomatic in 2 out of 3 cases but is thought to affect between 11% to 13% of women.


Adenomyosis is benign because it does not impact vital prognosis. However, it can strongly impact the daily life of patients due to potential intense pain. Furthermore, three symptoms are described:

  • Menorrhagia, which is long and heavy periods
  • Dysmenorrhea, which is pain linked to the menstrual cycle
  • Metrorrhagia, corresponding to blood loss outside the menstrual period.

What are the consequences of adenomyosis

Infertility is quite often associated with it since significant adenomyosis could be at the origin of an inflammatory process of the uterine wall, thereby preventing the implantation of the embryo within it.

However, treatments offered through medically assisted procreation (MAP) programs work well for this pathology and thus increase the chances of pregnancy.

How to manage adenomyosis?

How can adenomyosis be diagnosed?

Initially, the diagnosis of adenomyosis was made after a hysterectomy in women who no longer wished to have children or whose symptoms were excessively interfering with their daily lives.


Nowadays, diagnosis is possible thanks to less invasive imaging techniques such as magnetic resonance imaging (MRI) and transvaginal ultrasound.


What are the treatments for adenomyosis?

Currently, there appears to be no curative treatment for adenomyosis. Nevertheless, some management strategies allow for the treatment of symptoms: embolization (by introducing small gel beads) of the uterine arteries or taking hormonal substitutes that decrease the stimulation of endometrial tissues can help relieve menorrhagia.


Removal of the uterus or hysterectomy appears as the radical treatment for adenomyosis. Of course, this will be offered depending on the woman's age, her reproductive status, and the progression of her clinical symptoms.

In Brief:

Adenomyosis is a condition characterized by the migration of endometrial cells (from the innermost layer of the uterus) into the myometrium (the middle, muscular layer). This anomaly causes inflammation of the adjacent tissues, which in turn is responsible for the possible symptoms of the disease: pain, long and heavy periods, and a sensation of pelvic heaviness, among others. This pathology can also create fertility issues, but specialized support can help inhibit its potential symptoms and consequences.

Sources
  • Human Anatomy & Physiology, Elaine N. Marieb
    • Endofrance: French association for the fight against endometriosis
Back to blog