Understanding Thoracic Endometriosis

As a patient, you may already know that endometriosis is not just painful periods. Endometriosis, an inflammatory condition where endometriosis lesions can be found on tissues and organs in the abdomen and pelvis as well as elsewhere in the body, is relatively common, affecting an estimated 10% of women. However, these lesions are not isolated to the abdominopelvic cavity; they can also be found within the thoracic cavity, encompassing the lungs and diaphragm.  Endometriosis in the thoracic cavity is called thoracic endometriosis or thoracic endometriosis syndrome (TES).

Thoracic endometriosis is not as uncommon as is often assumed; it is likely underdiagnosed. Some of the symptoms one may experience are right shoulder blade or neck pain (90% of the pain presentation is on the right side), chest pain and shortness of breath, especially around menses (your period), coughing up blood, as well as lung collapse. Many sources suggest it impacts people in the 3rd and 4th decades and in those who have previously had a diagnosis of endometriosis. That being said, this may not be entirely accurate, but it is characteristic of those who’ve been diagnosed. If you have been experiencing unexplained chest pain or breathing difficulties, this may be caused by thoracic endometriosis. In this blog, we will explain what thoracic endometriosis is, what causes it, and how it can be treated.

The Manifestations: Decoding the Symptoms

Thoracic endometriosis is a master of disguise, often masquerading as other respiratory ailments, making it challenging to diagnose and treat effectively. The symptoms can range from subtle discomforts to life-threatening emergencies, and their cyclical nature, often coinciding with menstruation, is a telltale sign of this elusive condition.

Catamenial Pneumothorax: A Breath-Stealing Complication

One of the most alarming manifestations of thoracic endometriosis is catamenial pneumothorax, a condition where air leaks into the space between the lungs and the chest wall, altering the pressure differential and resulting in a collapsed lung. This complication occurs in approximately 73% of thoracic endometriosis cases and can lead to symptoms such as:

• Shortness of breath
• Chest pain
• Shoulder pain (often on the right side)
• Cough

The term “catamenial” refers to the cyclical nature of this condition, with the pneumothorax typically occurring within 72 hours of the onset of menstruation.

Catamenial Hemothorax: A Bloody Accumulation

Another manifestation of thoracic endometriosis is catamenial hemothorax, a condition where blood accumulates in the pleural space (the area between the lungs and the chest wall). This complication, while less common than catamenial pneumothorax, can still cause significant distress, with symptoms such as:

• Cough
• Shortness of breath
• Chest pain

Catamenial hemothorax predominantly affects the right side of the chest, although rare cases of left-sided involvement have been reported.

Catamenial Hemoptysis: Coughing Up Blood

In some cases, thoracic endometriosis can manifest as catamenial hemoptysis, a condition where the individual coughs up blood or experiences blood in their sputum. This symptom is relatively uncommon, occurring in only 7% of thoracic endometriosis cases, but it can be a distressing and potentially life-threatening complication.

Pulmonary Nodules: Unexpected Growths

Thoracic endometriosis can also present as pulmonary nodules, which are atypical growths in the lungs. These nodules can range in size from 0.5 to 3 cm and may or may not be accompanied by symptoms such as:

• Cough
• Shortness of breath
• Chest pain

While rare, accounting for only 6% of thoracic endometriosis cases, these nodules can be mistaken for more serious conditions, such as lung cancer, adding to the diagnostic challenge.

What Causes Thoracic Endometriosis?

The exact cause of thoracic endometriosis is still unknown. However, there are several theories that suggest it may be caused by:

Endometrial-Derived theories 

Commonly referred to as retrograde menstruation, the long-standing theory that endometrial cells are refluxed during menses, then morph into an endometriosis cell. From there, it is believed that this tissue can migrate to the thoracic cavity through congenital or acquired diaphragmatic fenestrations (openings) or via lymphatic or vascular dissemination. While this theory existed for a long time, there are likely better explanations to explain the presence of endometriosis.

Coelomic Metaplasia Theory

Another theory, known as the coelomic metaplasia theory, proposes that endometriosis lesions can arise from the transformation of mesothelial cells lining the pleura and peritoneal surfaces. This theory attempts to explain the presence of endometriosis in individuals without a functional endometrium, such as those with Mayer-Rokitansky-Küster-Hauser syndrome or men receiving high-dose estrogen therapy.

Prostaglandin Theory

The prostaglandin theory suggests that the cyclical nature of thoracic endometriosis symptoms may be linked to the increased production of prostaglandin F2α during menstruation. This potent constrictor of bronchioles and vasculature is believed to cause alveolar rupture and subsequent air leakage, potentially leading to conditions like catamenial pneumothorax.

The Lymphovascular Spread

Theory suggests that the endometrial cells can latch onto lymph nodes or vessels, which then transport them to the thoracic cavity.

The Diagnostic Journey: Overcoming the Challenges

Diagnosing thoracic endometriosis can be a daunting task, often involving a series of investigative steps and a high degree of clinical suspicion.

Imaging Modalities: Shedding Light on the Unseen

Several imaging techniques can aid in the diagnosis of thoracic endometriosis, including:

• Chest X-rays: While not specific, chest X-rays can reveal pneumothoraces, pleural effusions, or pulmonary nodules, raising suspicion for thoracic endometriosis.
• Computed Tomography (CT) scans: CT scans can provide detailed images of the lungs, revealing endometrial implants, pulmonary nodules, or diaphragmatic lesions.
• Magnetic Resonance Imaging (MRI): MRI is particularly useful in detecting diaphragmatic endometriosis, with a reported sensitivity of 78% to 83%.

However, it is important to note that imaging findings can be nonspecific, and a definitive diagnosis often requires further investigation.

Bronchoscopy and Tissue Sampling: Seeking Direct Evidence

While bronchoscopy and tissue sampling techniques, such as brush cytology or bronchial washings, have a limited diagnostic yield due to the peripheral location of endometrial implants, they can be valuable tools in certain cases. For instance, bronchoscopy performed within 1 to 2 days of the onset of menses may increase the chances of detecting endometrial tissue.

The Gold Standard: Video-Assisted Thoracoscopic Surgery (VATS)

The gold standard for diagnosing thoracic endometriosis is video-assisted thoracoscopic surgery (VATS), a minimally invasive procedure that allows direct visualization of the lungs, diaphragm, and pleural surfaces. During VATS, surgeons can identify and biopsy endometrial implants, diaphragmatic lesions, or other abnormalities, providing definitive evidence of thoracic endometriosis.

The Multidisciplinary Approach: Collaborative Care for Optimal Outcomes

Given the complexity of thoracic endometriosis and its potential involvement in both the thoracic and pelvic cavities, a multidisciplinary approach to treatment is often recommended. This collaborative effort typically involves the expertise of gynecologic and thoracic surgeons who are well-versed in the intricacies of endometriosis.

How Can Thoracic Endometriosis Be Treated?

Medical Management: Hormonal Therapy as the First Line

The initial therapies that may be used in general for endometriosis may be hormonal therapies for symptom management and are not treatments for endometriosis. Common medications used in this approach include:

• Gonadotropin-releasing hormone (GnRH) analogs
• Oral contraceptives
• Progestins
• Aromatase inhibitors
• GnRH antagonists

While these medications may provide symptom relief, they do not eliminate endometriosis, and they also may not work for everyone, moreover, the recurrence rate after discontinuing treatment can be as high as 60% within 12 months.

Surgical Intervention: A Multidisciplinary Endeavor

Surgical intervention is the only intervention that can actually remove the lesion, but it is still not a definitive treatment as recurrence is not uncommon, even with the best surgery.  

This surgery typically involves a combined approach, with video laparoscopy performed by a gynecologic surgeon to address pelvic endometriosis and video-assisted thoracoscopic surgery (VATS) conducted by a thoracic surgeon to treat thoracic lesions.

During VATS, surgeons can employ various techniques, including:

• Excision or ablation of the endometriosis lesions  on the lungs or diaphragm
• Resection of affected lung tissue or diaphragmatic fenestrations
• Pleurodesis (mechanical or chemical) to prevent recurrent pneumothoraces

Additionally, diaphragmatic defects or perforations may be repaired using endoscopic staplers or synthetic mesh, depending on the extent of the lesions.

Combination Therapy: Maximizing Outcomes

In many cases, a combination of surgical intervention and postoperative hormonal suppression therapy may be recommended to reduce the risk of disease recurrence. This multimodal approach has been shown to improve long-term outcomes and minimize the likelihood of symptom relapse.

The Elusive Diagnosis: Raising Awareness and Empowering Patients

Despite its potentially debilitating consequences, thoracic endometriosis often remains an elusive diagnosis, with many women experiencing a delay in receiving appropriate care. This delay can be attributed to various factors, including:

• Nonspecific symptoms that can be mistaken for other respiratory conditions
• Lack of awareness among healthcare providers about the manifestations of thoracic endometriosis
• Difficulty in establishing a clear link between symptoms and menstrual cycles

To address these challenges, raising awareness among both healthcare professionals and patients is crucial. Educating women about the potential manifestations of thoracic endometriosis and encouraging them to advocate for themselves can lead to earlier diagnosis and more timely interventions.

Thoracic Endometriosis and Fertility: Navigating the Challenges

For women with thoracic endometriosis who desire to conceive, the condition can present additional hurdles. While thoracic endometriosis itself does not directly impact fertility, it is often accompanied by pelvic endometriosis, which can contribute to infertility or subfertility.

In such cases, a comprehensive evaluation and treatment plan involving gynecologic and thoracic specialists is essential. Addressing both the pelvic and thoracic components of endometriosis may improve the chances of successful conception and a healthy pregnancy.

The Psychosocial Impact: Acknowledging the Emotional Toll

Living with thoracic endometriosis can take a significant emotional toll on individuals as they navigate the physical discomforts, diagnostic challenges, and treatment complexities associated with this condition. The cyclical nature of symptoms, often coinciding with menstrual cycles, can further exacerbate feelings of frustration, anxiety, and isolation.

It is crucial for healthcare providers to acknowledge and address the psychosocial impact of thoracic endometriosis, offering support and resources to help patients cope with the emotional challenges. Support groups, counseling, and mind-body therapies can be valuable tools in promoting overall well-being and resilience.

The Road Ahead: Ongoing Research and Future Perspectives

While our understanding of thoracic endometriosis has advanced significantly in recent years, there is still much to be explored and uncovered. Ongoing research efforts are focused on:

• Elucidating the precise mechanisms underlying the development and progression of thoracic endometriosis
• Improving diagnostic techniques for earlier and more accurate detection
• Developing novel therapeutic approaches, including targeted therapies and minimally invasive surgical techniques
• Exploring the potential role of genetics and environmental factors in the etiology of thoracic endometriosis
• Investigating the long-term consequences and impact on quality of life

By fostering collaboration among researchers, clinicians, and patient advocates, we can continue to advance our understanding of this enigmatic condition and pave the way for better outcomes and improved quality of life for those affected by thoracic endometriosis.

Conclusion: Embracing Hope and Resilience

Thoracic endometriosis, while not rare but often unrecognized, is a condition that demands our attention and compassion. By raising awareness, promoting early diagnosis, and embracing a multidisciplinary approach to treatment, we can empower individuals affected by this condition to reclaim their health and well-being.

Through ongoing research, innovative therapies, and a commitment to patient-centered care, we can navigate the challenges posed by thoracic endometriosis and offer hope and resilience to those who face this enigmatic journey.

References : 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4116267

https://www.medicalnewstoday.com/articles/thoracic-endometriosis

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6684338

https://endometriosis.net/living/thoracic-endo

https://www.topdoctors.co.uk/medical-articles/thoracic-endometriosis-explained

Updated: September 4, 2024