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Thoracic Endometriosis

by Tamer Seckin, MD | Posted on May 11, 2020


Thoracic Endometriosis Syndrome, Diaphragm fenestrations and  Extensive Scarringdue to endometriosis

Thoracic endometriosis is a form of extra-pelvic endometriosis that occurs when lesions spread to the diaphragm and the lungs. Due to the variety of organs involved, it is one of the most complex forms of endometriosis to surgically treat. It can be recognized on the dome of the diaphragm, the lung parenchyma (portion of the lung involved in gas transfer), visceral and parietal pleura (serous membrane that covers the surface of the lung and the outer membrane covering the thoracic cavity respectively), and even the tracheobronchial tree (branching airway passages of the respiratory system). Thoracic endometriosis is particularly challenging to identify unless respiratory symptoms are clear and present. Many physicians fail to establish a correlation between thoracic symptoms and a woman’s menstrual cycle. Thoracic endometriosis can be the source of catamenial pneumothorax (pneumothorax development during menstruation), catamenial hemothorax (blood collection in the pleural space during menstruation), catamenial hemoptysis (coughing up blood during menstruation) and lung nodules.

What is the thoracic cavity?

The thoracic cavity, or chest cavity as it is commonly knownThe thoracic cavity, commonly known as the chest cavity, is the chamber of the body protected by the rib cage and associated skin, muscle, and tissue. It contains two highly vital organ systems: the respiratory system (lungs, bronchi, esophagus, etc.) and the cardiovascular system (the heart and its blood vessels). It begins with the esophagus, right around the base of the neck, and ends with the diaphragm, which separates the thoracic cavity from the abdominal cavity. The central compartment of the thoracic cavity is mediastinum.

What is thoracic endometriosis?

Thoracic endometriosis is defined as the presence of endometrial tissue in or around the thoracic cavity, namely the lungs and diaphragm. It is a complex and rare condition, and proper diagnosis is often delayed. This can lead to recurrent hospitalizations and other medical complications.

What areas of the thoracic cavity can be affected by endometriosis?

Thoracic endometriosis can include any of the following regions:

  • Lungs: two saclike respiratory organs located on the left and right side of the thoracic cavity. The branching passages of the lungs allow for proper air exchange in a body.   

  • Pleura: the serous membranes that line the thoracic cavity and surround both lungs. The pleura has both an inner layer (visceral pleura) and out layer (parietal pleura), with an intermembrane space in between the two (pleural space).

  • Heart: the muscular organ that is responsible for pumping blood through the blood vessels of the circulatory system, providing the body with oxygen and nutrients.

  • Pericardium: the membrane surrounding the heart, composed of a fibrous outer layer, and inner double serous membrane.

  • Diaphragm: the long sheet of internal skeletal muscle that extends to the bottom of the thoracic cavity. In addition to playing a key role in how our body is able to breathe properly, the diaphragm separates the thoracic cavity from the abdominal cavity.

Endometriosis Adhesions of diaphragm to liver

What is a pneumothorax and how does it relate to endometriosis?

A pneumothorax is often marked by a total or partial collapsing of the lung. The image above shows a left lung pneumothorax (right side of the image).
A pneumothorax is often marked by a total or partial collapse of the lung. The image above shows a left lung pneumothorax (right side of the image).

Endometriosis lesions in the thoracic cavity are of a particular concern due to their association with catamenial pneumothorax (a collapsed lung occurring in conjunction with menstrual periods). When there is a small rupture in the lung, a pneumothorax occurs when air leaks out of the lungs into the space between it and the chest wall (pleural space). The higher pressure this creates against the lung wall (visceral pleura) can, in turn, cause the lung to partially or totally collapse.

A pneumothorax can be related to a variety of different disorders, namely diseases of the respiratory airways (i.e. COPD, severe, asthma, etc.) and infections of the lung (severe pneumonia, tuberculosis, etc.). However, when it comes to patients with endometriosis or a family history of endometriosis, concern will be raised if the pneumothorax is related to their menstrual periods (catamenial pneumothorax). If a patient is diagnosed with a pneumothorax, particularly in recurring cases, it is important to note if these symptoms coincide with her monthly menstrual cycle.

A pneumothorax is often marked by a total or partial collapse of the lung. The image above shows a left lung pneumothorax (right side of the image).

Why can thoracic endometriosis often go unnoticed?

Unfortunately, endometriosis can often go misdiagnosed by the average physician–and more so the case when dealing with lesions in the thoracic cavity. Unless there is chest pain, difficulty breathing, or other clear respiratory symptoms, thoracic endometriosis will not come to the attention of doctors. More importantly, when these symptoms do come up, rarely is a physician thinking of a possible thoracic endo case. Instead, the doctor will only look to rule out cardiovascular and respiratory issues. However, the truth of the matter is that no pneumothorax case should be discussed or treated without considering its primary origin, which, in some cases, can be the pelvis. When this goes unnoticed and in turn misdiagnosed, many of these patients do end up getting repeated thoracic surgeries without the patient or doctor knowing what is happening.

The important question to ask

While it is certainly important in cases of chest pain and shortness of breath to rule out cardiovascular and respiratory disease first, it is crucial that a physician considers the source of the symptoms. In cases where respiratory and cardiovascular tests are ruled unremarkable, but there are repeated instances of pneumothorax, and particularly when there is a history or family history of endometriosis, thoracic endometriosis should be considered. The key question for both a patient and doctor to ask is whether the clinical picture overlaps with the patient’s period. If a pneumothorax is recurrent and/or there is a relationship between the patient’s symptoms and their menstrual cycle, this could point to a cause of uterine origin, such as endometriosis.


While the common symptoms of endometriosis can certainly be associated with thoracic endometriosis, there are five distinct clinical entities that are of particular concern for endometriosis in the thoracic cavity:

  • Catamenial pneumothorax: This can be defined as a pneumothorax occurring in conjunction with a woman’s period. In other words, recurrent air leakage out of the lung and into the pleural space, with a particular association with one’s menstrual cycle. This should be of particular concern if a patient keeps getting hospitalized for a recurrent pneumothorax.

  • Catamenial hemothorax: A hemothorax is a collection of blood located in the space between the outer lung and the chest wall (pleural space). Thus, a catamenial hemothorax is a hemothorax in conjunction with menstruation. Once again, this is of particular concern to endometriosis patients when there is a recurrent hemothorax with no known cardiovascular or respiratory cause.

  • Catamenial hemoptysis: Defined as the coughing up of blood or blood-stained mucus, this is a common sign of many lung or respiratory infections. If this symptom is recurring around the time of menstruation, this could be yet another sign of the underlying cause of the symptoms or infection being related to thoracic endometriosis.

  • Pulmonary nodules: These small single masses in the lungs, while benign, can be the cause of other symptoms above such as hemoptysis. However, it is also important to consider the etiology of the nodules themselves, which when coupled with any of the symptoms above, can point towards endometriosis.

  • Catamenial chest pain and/or shortness of breath: Intermittent chest pain or shortness of breath is often attributed to cardiovascular or respiratory diseases. However, if a patient notes that they find their symptoms recurring monthly or specifically in synch with their menstrual cycle, it is important to alert one’s physician of this, as this can be a key clinical indication of thoracic endometriosis.



How to properly diagnose Thoracic Endometriosis?  

  • Medical history & physical examination: In order to diagnose thoracic endometriosis, a gynecologist must be highly thorough and meticulous in their medical history taking, as well as in their physical examination. It is important for a patient to let their doctor know if they have a history of recurrent pneumothorax, intermittent chest pain, and shortness of breath during their menstrual cycle, and if they have endometriosis or a family history of the disease as well. In terms of physical examination, if a patient has tenderness upon a pelvic and/or rectovaginal exam, with symptoms including catamenial chest pain or shortness of breath, and history of pneumothorax, these are all signs that can point towards thoracic endometriosis and warrant thoracic cavity inspection.

  • Imaging testing: One of the common ways a pneumothorax is diagnosed is via a chest x-ray. This is important to note as recurrent pneumothorax, particularly at the time of a woman’s period, is one of the key clinical indications of thoracic endometriosis. An endovaginal ultrasound is also critical as this can point towards endometriosis within the pelvic cavity, and thus the possible etiology of the catamenial symptoms themselves. A CT scan or MRI are also highly useful imaging tests that an endometriosis specialist may advise for further diagnostic testing.

  • Surgical diagnosis (laparoscopy & thoracoscopy): While imaging tests and meticulous medical history taking can all point towards inclinations of thoracic endometriosis, laparoscopic and thoracoscopic surgery are the primary ways to actually view lesions and confirm a diagnosis. Both are considered minimally invasive forms of surgery as they simply require small incisions, which a camera (scope) is then inserted through. The surgeon can then use excision clippers to cut out suspected endometriosis lesions, obtain a biopsy, and send it to a pathology lab for a confirmation of diagnosis. Thus laparoscopic excision and thoracoscopic excision/resection are the gold standards for surgically diagnosing a patient with suspected thoracic endometriosis.


Laparoscopy & Thoracoscopically

  • Endometriosis Adhesions of diaphragm to liver

    Laparoscopic excision: When it comes to surgically treating endometriosis located in the pelvic and abdominal cavity, laparoscopic excision surgery is the gold standard. It removes lesions while preserving healthy surrounding tissue, allowing the surgeon to obtain a biopsy sample to be sent to pathology to confirm a diagnosis. It is also a minimally invasive surgery that ensures minimal use of electricity and heat, ensuring for quicker recovery time and relief of symptoms. It is important to assess the pelvic and abdominal cavity for suspected thoracic endometriosis cases, as this can provide insight into the cause of the patient’s respiratory symptoms.

  • Thoracic excision/resection:  Suspected endometriosis lesions in the thoracic cavity can also be removed by minimally invasive surgery. Excision of these lesions is done via video-assisted thoracoscopic surgery (VATs). These lesions will either be excised individually or will require resection of part of the organ or membrane affected.

Why do surgeons have difficulty visualizing thoracic endometriosis?

Thoracic endometriosis is typically easier to recognize on the dome of the right side of the diaphragm. The caveat here is visualizing in direct view does not rule out endometriosis lesions that are obscured due to the curve of the liver. Therefore, doctors must use the technique of the 30-degree scope and look behind the liver by pressing down on it and examining the dome of the diaphragm. There may be lesions on the diaphragm that can reflect the pericardium, even on the right side. Therefore it is crucial to perform surgery alongside a thoracic surgeon in order to properly treat these lesions. The left side of the diaphragm can be performed the same way, but if one reaches the pericardium, it is imperative to have a thoracic surgeon on site.

Our Approach

Thoracic endometriosis remains a challenge for clinicians. When chest pain, shortness of breath, hemothorax, or recurrent pneumothorax occur in women of reproductive age, a diagnosis of diaphragmatic or thoracic endometriosis must be considered (Duyos, Lopez-Carrasco et al. 2014). Since there is a strong association of thoracic endometriosis with severe pelvic endometriosis and infertility, the necessity of thorough evaluation of the pelvis in patients with thoracic endometriosis to rule out possible pelvic endometriotic lesions is indicated. In many of these patients who are treated via video-assisted thoracoscopic surgery (VATs) by thoracic surgeons, the involvement of an experienced gynecologist is essential. Patients who desire to conceive should undergo excision of any pelvic endometriotic lesions (Soriano, Schonman et al. 2012).

The Dual Compartment Approach

The Duel Compartment ApproachUp to 80% of women with thoracic endometriosis also have endometriosis lesions in the abdominal/pelvic cavity, and yet the surgical treatment for the disease is typically performed in separate procedures (Camran, Nezhat et al. 2014). Therefore, we believe that when an endometriosis patient shows clinical signs of thoracic endometriosis, these patients need to have what we call Dual Compartment Approach. This is a combination of both minimally invasive laparoscopic surgery and video-assisted thoracoscopic surgery (VATs). In other words, a thoracoscopic surgeon should look through the thoracic cavity, while the gynecological surgeon looks through the abdominal and pelvic cavity for any signs of endometriosis lesions. The positive endometriosis findings within the pelvis in patients with a history of recurrent pneumothorax is an indication for thoracoscopic inspection.

Thorough Laparoscopic Excision Surgery for Thoracic Endometriosis

Diaphragm Mesh applicationIn addition to proper minimally-invasive visualization of both the abdominal/pelvic and thoracic cavity, we stress the importance of properly removing the endometriosis itself. Lesions can be taken out via laparoscopy and suture, but if there are lesions located within the thoracic cavity, thoracoscopy is needed and the lesions can be removed by staple, which we have done in our practice for many years. We have great experience in suturing transmurally through the full thickness of the diaphragm. There are even cases where we may apply a mesh covering–even when there is no obvious hole in the diaphragm, but the defects are visible and large–in order to prevent further pneumothorax or a history of pneumothorax. This procedure is often performed on patients with recurrent catamenial pneumothorax, along with possible lobectomies, partial lobectomies, and lung resection procedures.

The importance of assessing the diaphragm

Finally, in every laparoscopic examination, we ask specific questions to ensure that there is no history of pneumothorax. If there is, we believe that one of the first things that need to be assessed upon surgery, along with the liver and upper abdomen, is the status of the diaphragm.

If you feel you are suffering from recurrent chest pain and/or shortness of breath, are having a recurrent pneumothorax, and have a history of the family history of endometriosis, it is important to find the meticulous care and physicians that you both need and deserve to diagnose such a complex disease as thoracic endometriosis.

Ready for a Consultation?

Our endometriosis specialists are dedicated to providing patients with expert care. Whether you have been diagnosed or are looking to find a doctor, they are ready to help.

Our office is located on 872 Fifth Avenue New York, NY 10065.
You may call us at (646) 960-3080 or have your case reviewed by clicking here.

Patient Story

The Woman Was Fit and Healthy, Why Did Her Lung Mysteriously Collapse? The New York Times featured the care of an anonymous patient of the Seckin Endometriosis Center who was diagnosed with thoracic endometriosis. Even after undergoing pleurodesis (mechanical attachment of the lung to its pleural lining) by a thoracic surgeon, the patient continued to suffer from multiple episodes of catamenial pneumothorax. It was not until a dual compartment approach was performed, by both the Seckin Endometriosis Center and the patient’s thoracic surgeon, that the patient wasproperly diagnosed and surgically treated. 

You can read more stories of patients with thoracic endometriosis, and other varying stages of endometriosis, in our testimonial section.

Ready for a Consultation?

Our endometriosis specialists are dedicated to providing patients with expert care. Whether you have been diagnosed or are looking to find a doctor, they are ready to help.

Our office is located on 872 Fifth Avenue New York, NY 10065.
You may call us at (646) 960-3080 or have your case reviewed by clicking here.


  1. Endometriosis Foundation of America,
  2. Seckin, T., The Doctor Will See You Now: Recognizing and Treating Endometriosis. 2016.
  3. Parisa Azizad-Pinto, MD and David Clarke, MD, FCCP. “Thoracic Endometriosis Syndrome.”  The Permanente Journal, National Institute of Health (NIH). 2014 Summer; 18(3): 61–65.
  5. Sanders, Lisa, MD. “The Woman Was Fit and Healthy. Why Did Her Lung Mysteriously Collapse?” New York Times. March 28th, 2018.
  7. Nezhat, Camran, MD et al. “Multidisciplinary Treatment for Thoracic and Abdominopelvic Endometriosis.” Journal of the Society of Laparoendoscopic Surgeons, National Institute of Health. 2014 Jul-Sep; 18(3).
  9. Duyos, Lopez-Carrasco et al. “Management of thoracic endometriosis: Single Institution Experience.” European Journal of Obstetrics & Gynecology and Reproductive Biology. July 2014 Volume 178, Pages 56-59.
  10. //
  11. Soriano, David, MD et al. “Thoracic Endometriosis Syndrome is Strongly Associated With Severe Pelvic Endometriosis and Infertility.” The Journal of Minimally Invasive Gynecology. November-December, 2012 Volume 19, Issue 6, Pages 742-748.
  12. //



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