Thoracic Endometriosis: 11 Critical Signs to Know

Thoracic endometriosis is endometriosis involving structures inside the chest, most often the diaphragm and pleura around the lungs. It can also affect lung tissue and, less often, the airways.

Thoracic endometriosis may cause chest pain, shoulder pain, shortness of breath, coughing blood, fluid around a lung, or a collapsed lung. A major clue is that symptoms repeat near menstruation, although symptoms do not always follow a perfect monthly pattern.

The best known presentation is catamenial pneumothorax, which means a collapsed lung linked in time with menstruation. This can be a medical emergency.

This article is for general information and education. It does not replace medical advice, diagnosis, or treatment.

Thoracic Endometriosis: Quick Answer

Thoracic endometriosis occurs when endometriosis affects the chest, including the diaphragm, pleura, lung tissue, or airways.

The condition may cause:

• Chest pain
• Shoulder pain
• Shortness of breath
• Collapsed lung
• Blood around the lung
• Coughing blood
• Recurring chest symptoms around menstruation

The symptoms are often strongest within a few days of the start of menstruation, but they can occur outside that window too.

The condition can be difficult to diagnose because chest pain and breathlessness have many other causes.

What Is Thoracic Endometriosis?

Endometriosis is a condition in which tissue similar to the lining of the uterus grows outside the uterus.

Most endometriosis occurs in the pelvis.

Thoracic disease is less common and may affect:

• The diaphragm
• The pleura
• The lung tissue
• The chest cavity
• Rarely, the airways

When these chest related problems occur as part of endometriosis, doctors may use the term thoracic endometriosis syndrome.

How Common Is Thoracic Endometriosis?

Thoracic endometriosis is considered uncommon, but its true frequency is uncertain because diagnosis is often delayed or missed.

A 2024 systematic review examined 592 reported patients with pulmonary or thoracic endometriosis.

The median age was about 34 years.

The most commonly reported presentation was catamenial pneumothorax.

The same review found a strong right sided pattern.

Other research suggests that many people with thoracic disease also have pelvic endometriosis.

Why Does Thoracic Endometriosis Often Affect the Right Side?

One striking feature of thoracic endometriosis is that it often affects the right chest.

The exact reason is not fully settled.

Several theories have been proposed, including the movement of cells or fluid through the abdominal cavity and through small openings in the diaphragm.

The diaphragm itself may also contain endometriosis lesions.

Right sided disease is therefore an important clue, but left sided and bilateral disease can occur.

11 Critical Signs of Thoracic Endometriosis

1. Chest Pain That Repeats Around Your Period

Cyclic chest pain is one of the most useful clues.

The pain may be:

• Sharp
• Stabbing
• Aching
• Worse with breathing
• Focused on one side

Some people notice that it appears at roughly the same point in each menstrual cycle.

Chest pain should never automatically be blamed on endometriosis because heart and lung conditions can produce similar symptoms.

2. Shortness of Breath

Breathlessness may happen if thoracic endometriosis causes a pneumothorax, bleeding, inflammation, or other chest involvement.

It may feel like:

• You cannot take a full breath
• Your breathing becomes suddenly difficult
• You get winded with very little activity
• You need to breathe faster than usual

Sudden or severe breathlessness needs urgent assessment.

3. Catamenial Pneumothorax

Catamenial pneumothorax is a collapsed lung that occurs in a close time relationship with menstruation.

A 2026 review describes it most commonly within about 72 hours before or after the start of menstruation.

Symptoms can include:

• Sudden chest pain
• Shortness of breath
• Fast breathing
• Shoulder pain
• Rapid heart rate

The symptoms do not have to occur with every menstrual cycle.

4. Shoulder Pain

Pain from the diaphragm can sometimes be felt in the shoulder.

This is called referred pain.

Right shoulder pain that repeatedly occurs around menstruation can be an important clue, especially when pelvic endometriosis or chest symptoms are also present.

5. Upper Abdominal or Diaphragm Pain

Diaphragmatic endometriosis may cause pain beneath the ribs or in the upper abdomen.

Some people describe pain that spreads toward the shoulder or chest.

The pain may worsen with deep breathing.

6. Coughing Up Blood

Catamenial hemoptysis means coughing blood that is linked with menstruation.

This is an uncommon presentation but can occur when endometriosis affects lung tissue or airways.

Coughing blood should always be medically assessed because many other lung conditions can cause it.

7. Blood Around the Lung

Catamenial hemothorax means blood collecting in the pleural space around a lung in association with menstruation.

Possible symptoms include:

• Chest pain
• Shortness of breath
• Weakness
• Fast heartbeat

This requires prompt medical care.

8. Repeated Symptoms on the Right Side

Thoracic endometriosis often affects the right side.

In a 2024 systematic review, right sided thoracic lesions were much more common than left sided disease.

This pattern is useful diagnostically, but it is not absolute.

9. Pelvic Endometriosis Symptoms

Many people with thoracic disease also have pelvic endometriosis.

Possible pelvic symptoms include:

• Severe period pain
• Pelvic pain
• Pain during or after sex
• Pain with bowel movements
• Pain when urinating
• Infertility

Tell your healthcare team about both chest and pelvic symptoms because the combination can provide an important clue.

10. Repeated Emergency Visits for Similar Chest Symptoms

Some people experience several episodes of chest pain or pneumothorax before the connection with menstruation is recognised.

If chest symptoms keep returning, write down:

• The date symptoms started
• The date menstruation started
• Which side hurt
• Whether breathlessness occurred
• Imaging results
• Previous diagnoses

A simple symptom calendar can reveal a pattern that is easy to miss during a single visit.

11. Symptoms That Repeatedly Follow the Menstrual Cycle

This timing is one of the strongest clues.

However, not every thoracic endometriosis symptom happens exactly during menstruation.

Some symptoms can appear before, during, or shortly after a period.

Others become less predictable over time.

Thoracic Endometriosis Symptoms at a Glance

What Is Catamenial Pneumothorax?

The word “catamenial” means related to menstruation.

A catamenial pneumothorax is therefore a collapsed lung that happens in a close time relationship with a menstrual period.

It is strongly associated with thoracic endometriosis, although endometriosis lesions are not identified in every person who has this type of pneumothorax.

Catamenial pneumothorax is the most commonly reported form of thoracic endometriosis syndrome.

Is Thoracic Endometriosis Always Linked to Periods?

No.

A clear menstrual pattern makes the diagnosis easier to suspect, but symptoms can also occur at other times.

This means thoracic endometriosis should not be completely dismissed simply because one episode happened outside menstruation.

Can Thoracic Endometriosis Cause Back Pain?

It can cause pain that spreads through the chest, shoulder, ribs, or upper back.

Back pain has many possible causes, so it is not specific to endometriosis.

A repeating connection with menstruation makes thoracic or diaphragmatic disease more important to consider.

Can Thoracic Endometriosis Cause Rib Pain?

Yes, some people describe pain near the lower chest or ribs, especially with diaphragmatic disease.

The pain can sometimes become worse during deep breathing.

Can Thoracic Endometriosis Cause a Cough?

Yes.

Some people experience cough, and a much smaller group may cough blood.

A new persistent cough should still be assessed for other causes because respiratory infection, asthma, reflux, medication effects, and lung disease are much more common.

Thoracic Endometriosis Versus Pulmonary Embolism

Both can cause:

• Chest pain
• Shortness of breath
• Fast heart rate
• Coughing blood

A pulmonary embolism is a potentially life threatening blood clot in the lungs.

Do not assume chest symptoms are endometriosis just because they happen around menstruation.

Sudden unexplained chest pain or breathlessness requires urgent assessment.

Thoracic Endometriosis Versus Asthma

Asthma often causes:

• Wheezing
• Cough
• Chest tightness
• Breathlessness

Thoracic endometriosis is more likely to raise suspicion when symptoms recur around menstruation, especially if there has been a pneumothorax or marked one sided chest pain.

How Is Thoracic Endometriosis Diagnosed?

Diagnosis often begins with a detailed history.

Your clinician may ask about:

• Timing of chest symptoms
• Menstrual cycle dates
• Previous pneumothorax
• Pelvic pain
• Severe periods
• Infertility
• Previous endometriosis
• Previous chest imaging

Imaging and sometimes surgery are then used to investigate further.

Chest X Ray

A chest X ray is often one of the first tests when pneumothorax is suspected.

It can show:

• A collapsed lung
• Pleural fluid
• Other major chest abnormalities

A normal chest X ray does not rule out thoracic endometriosis.

CT Scan

A chest CT gives more detail than an ordinary X ray.

It can help detect:

• Pneumothorax
• Pleural abnormalities
• Lung nodules
• Cysts
• Ground glass changes
• Other causes of chest symptoms

CT findings are not always specific for endometriosis.

MRI

MRI can be useful when diaphragmatic endometriosis is suspected.

It avoids ionising radiation and may provide useful soft tissue detail.

Imaging quality and interpretation matter because small lesions can still be missed.

Can Scans Miss Thoracic Endometriosis?

Yes.

A normal scan does not completely exclude thoracic or diaphragmatic endometriosis.

Some lesions are small, superficial, or difficult to see outside a symptomatic period.

This is one reason the history and menstrual timing remain important.

Does Timing Imaging Around a Period Help?

In selected cases, clinicians may consider whether imaging during symptoms could provide more information.

However, there is no simple rule that everyone must have imaging during menstruation.

The decision should be made by the treating team.

What Is Video Assisted Thoracoscopic Surgery?

Video assisted thoracoscopic surgery, often called VATS, is minimally invasive chest surgery.

A surgeon uses a camera and small instruments through limited chest incisions.

VATS may allow the team to:

• Inspect the pleura
• Inspect the diaphragm
• Remove visible lesions
• Repair diaphragm defects
• Treat recurrent pneumothorax
• Collect tissue for pathology

When pelvic or diaphragmatic disease is also suspected, a gynecologic surgeon may perform laparoscopy during the same planned treatment.

Why a Multidisciplinary Team Matters

Thoracic endometriosis can involve both the chest and pelvis.

Care may therefore involve:

• A gynecologist with endometriosis expertise
• A thoracic surgeon
• A pulmonologist
• A radiologist
• A pain specialist
• Other clinicians depending on fertility goals and health needs

Modern reviews increasingly support this combined approach.

How Is Thoracic Endometriosis Treated?

Treatment depends on:

• Symptoms
• Previous pneumothorax
• Disease location
• Recurrence
• Fertility goals
• Other health conditions
• Whether hormone treatment is suitable

There is no single treatment that is best for everyone.

Hormonal Treatment

Hormonal treatment aims to suppress ovarian hormone cycling and reduce endometriosis activity.

Options may include:

• Combined hormonal contraceptives
• Progestogens
• GnRH agonists
• GnRH antagonists in selected settings

The choice depends on symptoms, contraindications, side effects, fertility goals, and specialist advice.

Hormonal therapy may control symptoms, but recurrence can occur after treatment stops.

When Is Surgery Considered?

Surgery may be considered when:

• Pneumothorax keeps returning
• Symptoms continue despite medical treatment
• Hormonal treatment is not suitable
• Significant diaphragm disease is suspected
• A structural chest problem needs repair

The decision is individual.

Does Hysterectomy Cure Thoracic Endometriosis?

No.

This is an important correction to a common misconception.

Removing the uterus does not automatically remove endometriosis from the chest or diaphragm.

Endometriosis is not simply a disease of the uterus.

Hysterectomy may be appropriate for certain pelvic conditions in selected patients, but it is not a standard stand alone cure for thoracic endometriosis.

Can Thoracic Endometriosis Come Back After Surgery?

Yes.

Recurrence is possible even after surgery.

A recent meta analysis involving 1,182 surgically treated patients found meaningful rates of recurrent pneumothorax and repeat surgery.

This is why surgery may be combined with postoperative hormonal suppression in selected patients.

Can Thoracic Endometriosis Affect Fertility?

Thoracic disease itself does not necessarily cause infertility.

However, many patients also have pelvic endometriosis, which can affect fertility.

If future pregnancy matters to you, discuss fertility plans before beginning long term hormonal treatment or major surgery.

Can You Get Thoracic Endometriosis Without Pelvic Endometriosis?

Yes.

Thoracic disease can occur without known pelvic disease.

However, concurrent pelvic endometriosis is common enough that clinicians often ask about pelvic symptoms when thoracic disease is suspected.

Can Thoracic Endometriosis Happen After Menopause?

Endometriosis is much more common before menopause because it is hormone responsive.

However, persistent or recurrent disease after menopause has been reported.

Chest symptoms after menopause still need a broad medical assessment because many other causes become more likely.

Does Pregnancy Cure Thoracic Endometriosis?

No.

Pregnancy can change endometriosis symptoms because hormone patterns change, but pregnancy is not a cure for endometriosis.

Symptoms may return later.

Can Diet Cure Thoracic Endometriosis?

No specific diet has been proven to remove thoracic endometriosis lesions or prevent pneumothorax.

A balanced diet may support general health, but it should not replace medical or surgical treatment.

Be cautious with online claims that one food, herb, detox, or supplement can cure endometriosis.

Can Exercise Help?

Regular activity can support general health and mood when symptoms allow.

However, exercise does not treat a collapsed lung or active thoracic complication.

If you recently had a pneumothorax, chest procedure, or surgery, ask your medical team when it is safe to return to exercise.

How to Prepare for a Medical Appointment

A clear timeline can make a major difference.

Bring information about:

1. The dates of your last several periods.
2. The exact dates chest symptoms started.
3. Which side of the chest or shoulder hurt.
4. Whether you had shortness of breath.
5. Any history of pneumothorax.
6. Previous X rays, CT scans, or MRI reports.
7. Pelvic pain or severe periods.
8. Past endometriosis diagnosis or surgery.
9. Current hormonal medicines.

A Symptom Diary Can Reveal the Pattern

Use a calendar for at least several cycles if your symptoms are stable enough to do so.

Record:

• Menstrual bleeding
• Chest pain
• Shoulder pain
• Breathlessness
• Cough
• Pelvic pain
• Any emergency visits

Do not use symptom tracking to delay urgent care when breathing becomes difficult or chest pain is severe.

When Chest Pain Is an Emergency

Seek urgent or emergency care for:

• Sudden severe chest pain
• Sudden shortness of breath
• Difficulty breathing at rest
• Blue or grey lips
• Fainting
• Rapid worsening
• Coughing significant blood
• Severe weakness

A collapsed lung, pulmonary embolism, severe bleeding, heart condition, or another emergency must be ruled out.

Common Thoracic Endometriosis Myths

Myth 1: It Always Happens During a Period

False.

Menstrual timing is an important clue, but symptoms may occur before, during, or after bleeding and may not happen every cycle.

Myth 2: It Always Affects the Lung Tissue

False.

The diaphragm and pleura are important sites of disease.

Myth 3: A Normal CT Rules It Out

False.

Imaging can miss small or subtle lesions.

Myth 4: A Hysterectomy Automatically Cures It

False.

Removing the uterus does not automatically remove chest endometriosis.

Myth 5: Every Episode of Chest Pain During a Period Is Thoracic Endometriosis

False.

Heart, lung, muscle, digestive, and anxiety related causes can produce chest pain too.

Myth 6: It Is Never Serious

False.

A pneumothorax or hemothorax can require urgent hospital treatment.

Questions to Ask Your Specialist

1. Could my chest symptoms be linked with my menstrual cycle?
2. Do I need chest imaging?
3. Could my diaphragm be involved?
4. Should I be assessed for pelvic endometriosis too?
5. Would hormonal treatment be suitable for me?
6. When should thoracic surgery be considered?
7. Would combined thoracic and gynecologic surgery be useful?
8. What is my risk of recurrence?
9. How could treatment affect fertility plans?

Conclusion

Thoracic endometriosis is an uncommon but important form of endometriosis involving the diaphragm, pleura, lungs, or other structures in the chest.

The strongest clue is often a repeating pattern of chest pain, shoulder pain, breathlessness, pneumothorax, or other chest symptoms around menstruation.

Catamenial pneumothorax is the most frequently reported presentation, and the right side is affected far more often than the left.

Diagnosis may require careful menstrual history, chest imaging, pelvic assessment, and sometimes minimally invasive surgery. Treatment can include hormonal therapy, thoracic surgery, gynecologic surgery, or a combination depending on the individual case.

Your next step is simple: if you notice recurring chest or shoulder symptoms around menstruation, record the timing and tell your healthcare professional. If chest pain or breathing difficulty is sudden or severe, seek urgent medical care rather than waiting for the menstrual cycle to pass.

References and Sources

1. Nezhat C, Amirlatifi N, Najmi Z, Tsuei A. Thoracic Endometriosis Syndrome: A Comprehensive Review and Multidisciplinary Approach to Management. Journal of Clinical Medicine. 2024.
   https://pmc.ncbi.nlm.nih.gov/articles/PMC11678721/
2. Pulmonary Endometriosis: A Systematic Review. Journal of Personalized Medicine. 2024.
   https://pmc.ncbi.nlm.nih.gov/articles/PMC11595740/
3. American College of Obstetricians and Gynecologists. Diagnosis of Endometriosis. Clinical Practice Guideline. March 2026.
   https://www.acog.org/clinical/clinical-guidance/clinical-practice-guideline/articles/2026/03/diagnosis-of-endometriosis
4. European Society of Human Reproduction and Embryology. ESHRE Guideline: Endometriosis.
   https://www.eshre.eu/Guidelines-and-Legal/Guidelines/Endometriosis-guideline
5. Thoracic Endometriosis Syndrome: A Review of Diagnosis and Management.
   https://pmc.ncbi.nlm.nih.gov/articles/PMC6684338/
6. Catamenial Pneumothorax: Still an Unveiled Disease.
   https://pubmed.ncbi.nlm.nih.gov/39768909/
7. Thoracic Endometriosis Syndrome: A Systematic Review and Meta Analysis of Surgical Outcomes Among 1,182 Patients Over 25 Years.
   https://pubmed.ncbi.nlm.nih.gov/41419079/

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About the Author

Adel Galal is the founder and editor of NextFitLife. He writes practical consumer health, wellness, nutrition, fitness, and healthy ageing content using information from recognized medical, public health, and academic sources.

I am not a doctor, gynecologist, pulmonologist, thoracic surgeon, pharmacist, or other licensed healthcare professional. This content does not replace professional medical advice. What I share comes from real life experience, extensive research, and consultation with healthcare providers. Always consult qualified medical professionals for diagnosis and treatment of any health condition.

Learn more about NextFitLife, the author, and the site's editorial approach on the About Us page.

Frequently Asked Questions

What is thoracic endometriosis?

Thoracic endometriosis is endometriosis affecting structures in the chest, most often the diaphragm and pleura, but sometimes the lung tissue or airways.

What does thoracic endometriosis feel like?

It may cause chest pain, shoulder pain, upper abdominal pain, shortness of breath, cough, or other chest symptoms. Symptoms often repeat around menstruation.

What is catamenial pneumothorax?

Catamenial pneumothorax is a collapsed lung that occurs in close relation to menstruation. It is the most frequently reported presentation of thoracic endometriosis syndrome.

Is thoracic endometriosis serious?

It can be. A pneumothorax, hemothorax, or significant breathing problem may require urgent hospital treatment.

Why is thoracic endometriosis usually on the right side?

The exact reason is not fully understood. Proposed explanations include movement of cells or fluid through the abdomen and diaphragm, but right sided disease is much more commonly reported.

Can thoracic endometriosis cause shoulder pain?

Yes. Endometriosis affecting the diaphragm can cause referred pain felt in the shoulder, often on the right side.

Can thoracic endometriosis cause coughing blood?

Yes. Catamenial hemoptysis is an uncommon form of thoracic endometriosis in which coughing blood occurs in association with menstruation.

How is thoracic endometriosis diagnosed?

Diagnosis uses the symptom pattern, menstrual history, chest imaging, assessment for pelvic endometriosis, and sometimes video assisted thoracoscopic surgery or laparoscopy.

Can a CT scan miss thoracic endometriosis?

Yes. CT can identify pneumothorax and other chest changes, but small or subtle endometriosis lesions may not be visible.

How is thoracic endometriosis treated?

Treatment may include hormonal suppression, thoracic surgery, gynecologic surgery, or a combination. The choice depends on symptoms, recurrence, disease location, fertility goals, and individual health factors.

Does hysterectomy cure thoracic endometriosis?

No. Removing the uterus does not automatically remove endometriosis from the diaphragm, pleura, or lungs, so hysterectomy is not a stand alone cure for thoracic endometriosis.

Can thoracic endometriosis return after surgery?

Yes. Recurrence can occur after surgery, which is why some patients are offered postoperative hormonal treatment and ongoing specialist follow up.

When should chest symptoms be treated as an emergency?

Seek urgent help for sudden severe chest pain, severe shortness of breath, fainting, blue or grey lips, rapidly worsening breathing, or coughing significant blood.