What Is Diaphragmatic Endometriosis?

Medically reviewed by Renita White, MD

Diaphragmatic endometriosis is a rare form of endometriosis in which tissue that usually lines the inside of the uterus is found in the diaphragm, the dome-shaped muscular organ that separates the lungs and heart from the stomach, intestines, and surroundings.

Endometriosis usually appears in the pelvic region. In rare cases, it can appear in other places, like the diaphragm. About 6% to 10% of people who experience menstruation experience endometriosis. Diaphragmatic endometriosis affects about 0.2% to 1.5% of people with endometriosis.

This article covers the symptoms and causes of diaphragmatic endometriosis, how diaphragmatic endometriosis is diagnosed, and when to seek care.

How Diaphragmatic Endometriosis Differs From Standard Endometriosis

The endometrium is the tissue that lines the cavity of the uterus (the womb). Endometriosis is when tissue that mimics the endometrium grows outside of the uterus. This tissue is usually called patches or lesions.

Diaphragmatic endometriosis is when endometriosis reaches the diaphragm, the dome-shaped organ that separates the lungs and heart from the stomach and intestines. In addition to the typical symptoms of endometriosis, diaphragmatic endometriosis can affect the respiratory system.

Symptoms of Diaphragmatic Endometriosis

Only about 25% of people with diaphragmatic endometriosis experience obvious symptoms. Most symptoms of diaphragmatic endometriosis can seem to be caused by other factors. This might be why the condition is likely to be diagnosed during surgery for standard endometriosis.

The most common symptoms of diaphragmatic endometriosis include:

• Infertility

• Dyspnea (labored breathing)

• Shoulder pain (from damage to the phrenic nerve linking the brain and the diaphragm)

• Pain when taking a deep breath during periods

Other symptoms include:

• Upper abdominal pain

• Neck or ear pain

• Nausea and vomiting

• Cough or coughing blood

• In rare cases, collapsed lung

Causes

There are several theories to explain the causes of diaphragmatic endometriosis, including:

• Menstrual reflux theory: Cells that build tissue in the uterus are transported to the diaphragm in fluids that travel backward from the pelvis to the diaphragm.

• Coelomic metaplasia hypothesis: Metaplasia is when a cell inside a tissue is replaced by another type of cell that is not normal to the tissue. This is caused by environmental stress (like smoking, hormonal changes, chemical reactions, etc.). Cells that usually line the uterus could replace cells near the diaphragm.

• Benign metastasis: Endometrial cells are distributed throughout the body through fluids such as blood.

• Stem cell theory: The fluid that lines the uterus grows stem cells, which are cells that can grow into different types of cells.

• Epigenetic/genetic: Some people's uterine lining could need more repair than others when it is affected by the environment or when it sheds (such as during periods). Signs could appear as early as infancy or later in childhood.

Diaphragmatic Endometriosis Diagnosis

Because about 75% of people with diaphragmatic endometriosis do not experience clear symptoms, the condition can be difficult to diagnose. The most common way diaphragmatic endometriosis is found is during laparoscopic surgery for endometriosis. This is when lesions are removed by a surgeon using a thin tube with a light and camera attached that is inserted through a small cut in the abdomen or pelvis.

Other ways to diagnose diaphragmatic endometriosis include:

• Magnetic resonance imaging (MRI): This scan uses magnets and radio waves to create images of the inside of the body. MRIs don't capture every occurrence of diaphragmatic endometriosis, but they are likely to work 80% of the time.

• Chest radiographs (X-rays) or computed tomography (CT) scans: Chest X-rays can pinpoint abnormalities in the air or blood in the lungs, even if it is not the most sensitive to diaphragmatic endometriosis.

• Preoperative abdominal ultrasound: An ultrasound before pelvic surgery. This test is only 15% likely to diagnose diaphragmatic endometriosis.

Treatment

Treatment for diaphragmatic endometriosis depends on symptoms. If there are no symptoms, healthcare providers usually take an expectant approach, meaning the condition is monitored instead of removed with surgery.

Diaphragmatic endometriosis with symptoms is usually treated via:

• Hormonal medications: Hormone therapy, such as birth control pills, can help suppress the growth of lesions. Hormone therapy can prevent hormones from being produced by the ovaries or limit the length of periods to decrease pain. It also can interfere with fertility and prevent pregnancy. Discontinuing hormonal medication can make the lesions reappear.

• Pain relief medications: These could include over-the-counter (OTC) nonsteroidal anti-inflammatory drugs (NSAIDs) like Advil or Motrin (ibuprofen), Aleve (naproxen), and aspirin, or prescription painkillers, like opioids (codeine).

• Laparoscopic surgery: Laparoscopic surgery, which in this case is called video-assisted thoracoscopic surgery (VATS), involves inserting a slim tube with a light and camera attached through a small incision in the abdomen in which to remove lesions. The lesions are removed either with a laser or an incision.

Complications and Outlook

If left untreated, diaphragmatic endometriosis could result in:

• Trouble breathing

• Bleeding into the lungs or collapsed lung

• Rupture of the diaphragm

• Irreversible infertility

• Pain in the chest, shoulders, and surrounding areas

• Depression or anxiety because of chronic pain and social isolation

• Economic burdens from taking time off work and long-term treatment

It's advised to get a diagnosis of diaphragmatic endometriosis as soon as possible so it can be monitored.

There is no cure for endometriosis. However, lesions can be removed, and symptoms managed with medication. When treated with surgery and continued hormonal treatment, diaphragmatic endometriosis symptoms can stop. According to one study, 61% of people who undergo surgery for diaphragmatic endometriosis feel relief from their symptoms.

Diaphragmatic Endometriosis and Fertility

Almost 50% of people with diaphragmatic endometriosis experience infertility vs. about 30% of people with standard endometriosis. This could be because diaphragmatic endometriosis is more likely in people with already severe pelvic endometriosis.

Research published in 2023 found that almost 44% of small-study participants became pregnant after surgery to remove diaphragmatic endometriosis lesions. Since treating diaphragmatic endometriosis includes hormone therapy, fertility can be affected by treatment. It's advised to opt for surgery, if possible, if fertility is a concern or symptom (along with shoulder pain and other symptoms of diaphragmatic endometriosis).

Can Diaphragmatic Endometriosis Be Fatal?

There is no data to suggest that diaphragmatic endometriosis is fatal. However, it's advised to get treatment as soon as possible because of potential complications like:

• Collapsed lung

• Lung hemorrhaging

• Coughing up blood at life-threatening levels (rare)

There might also be a risk of nerve damage from surgery to remove diaphragmatic endometriosis.

When to Seek Care

Seek a diagnosis and care for endometriosis as soon as possible, considering the condition can spread to other organs and interfere with daily life and mental health.

A diaphragmatic endometriosis is advised if you experience shoulder pain while having endometriosis. Infertility during endometriosis is also a possible indicator of the disorder. Considering the risk of complications like lung collapse, it is highly advised to monitor diaphragmatic endometriosis while treating it with hormonal medications.

Summary

Diaphragmatic endometriosis is endometriosis that reaches the diaphragm, a muscle located beneath the lungs. Symptoms of diaphragmatic endometriosis include coughing or coughing up blood, shoulder pain, labored breathing, endometriosis in the left pelvis, and infertility while having endometriosis.

Diaphragmatic endometriosis might be caused by fluids that cycle from the pelvic region to the diaphragm or abnormal cell activity, such as cells from one part of the body growing in another. The condition might be genetic.

Treating diaphragmatic endometriosis usually requires monitoring symptoms while taking hormonal medications to reduce lesions. If the condition begins to show obvious symptoms, surgery is usually recommended. Diaphragmatic endometriosis can be serious considering the risk of lung collapse or, in rare cases, excessive bleeding from coughing. It's advised to seek care as soon as diaphragmatic endometriosis symptoms occur.