Medically reviewed by Peter Weiss, MD
Endometriosis is a medical condition that causes the type of cells that usually line the uterus to grow in other parts of the body. These patches of tissue are called endometrial implants.
Thoracic endometriosis is a rare form of endometriosis that causes endometrial implants to grow around or inside the lungs. This type of endometriosis—in which implants occur outside the reproductive organs and pelvic area—is known as extragenital endometriosis. Many people with extragenital endometriosis also have pelvic (or "typical") endometriosis, which can affect the ovaries, fallopian tubes, rectum, intestines, bladder, and the space behind the uterus.
In this article, we’ll go over everything you need to know about thoracic endometriosis, including symptoms, causes, and possible treatment options.
In the United States, about 10% of women in their reproductive years have endometriosis.
Symptoms of Thoracic Endometriosis
Many people with endometriosis don’t experience any symptoms. Those who do often notice that their symptoms show up or get worse around the time of their period.
People with thoracic endometriosis may experience any of the following signs and symptoms:
Pelvic pain, especially during sex, urination, and/or bowel movements
Irregular or heavy periods
Lower back pain
Shortness of breath
Right shoulder pain
Coughing or wheezing
Coughing up blood
Causes of Thoracic Endometriosis
Thoracic endometriosis occurs when patches of tissue that would typically be found in uterine lining grow in areas of the thorax (chest) instead.
Endometrial implants—also known as nodules or lesions—may be found in the lung itself, as well as in or around the diaphragm, bronchi (airways), or pleura (the tissue that lines and protects the inside and outside of the lungs). During your period, these implants may get inflamed or bleed, causing symptoms like dyspnea (shortness of breath).
No single known cause of endometriosis has been identified. However, some researchers believe that the condition may be caused by retrograde menstruation, in which blood flows backward into the pelvic area during the menstrual cycle. Others argue that endometriosis is related to an alteration in the types of the cells that line the uterus.
There are several risk factors that may increase your chance of developing endometriosis, including:
Having a close relative with the disorder
Having no children
Starting your period before the age of 11
Having short menstrual cycles, frequent periods, or heavy menstrual bleeding
Thoracic Endometriosis Complications
Several complications can occur when thoracic endometriosis is left untreated, including catamenial pneumothorax, hemothorax, hemoptysis, and lung nodules.
About 80% of people with thoracic endometriosis experience a complication known as catamenial pneumothorax. “Catamenial” refers to a symptom that appears only around the time of your period, while “pneumothorax” refers to a collapsed lung. Catamenial pneumothorax is defined as a recurrent collapsed lung that occurs within 72 hours of menstruation.
The symptoms of catamenial pneumothorax include coughing, shortness of breath, and chest pain. The pain can also radiate to the neck and shoulder, typically on the right side of the body.
Around 14% of people with thoracic endometriosis experience catamenial hemothorax, which refers to a buildup of blood between the lining of the lungs. Like catamenial pneumothorax, this complication can cause difficulty breathing as well as pain in the shoulder, chest, and/or neck. In the vast majority of cases, this pain occurs on the right side.
Catamenial hemoptysis (coughing up blood) occurs in approximately 5% of cases of thoracic endometriosis. Usually, the bleeding is mild to moderate. Severe, life-threatening blood loss is possible, but extremely rare.
Very rarely, thoracic endometriosis can lead to the development of lung nodules. These lesions typically vary from 0.5 to 3 centimeters in diameter. They are sometimes noticed on imaging tests during the process of diagnosing endometriosis.
How Is It Diagnosed?
To diagnose you with thoracic endometriosis, your healthcare provider may perform a pelvic exam and/or ultrasound, in addition to asking you about your medical and family histories, symptoms, fertility, and menstrual cycles.
Your healthcare provider may also use the following tests to determine whether or not you have endometrial implants in your chest cavity (or anywhere else):
Computed tomography (CT) scan
Chest radiographs (X-rays)
Bronchoscopy, which involves viewing the inside of your lungs with a thin tube with a light and lens attached
Pelvic laparoscopy, which involves looking inside your pelvic area with a thin tube containing a light and camera
Thoracic Endometriosis Treatment
Thoracic endometriosis is typically treated with hormone therapy, surgery, or both.
Hormone therapy is typically the first-line treatment for endometriosis. The goals of hormone therapy are to relieve pain, shrink or slow down the growth of existing endometrial implants, and prevent new ones from forming.
Your healthcare provider may prescribe any of the following medications to treat thoracic endometriosis:
Combination hormonal birth control
Gonadotropin-releasing hormone (GnRH) analogs or antagonists to stop your ovaries from producing estrogen
If your endometriosis symptoms don’t resolve with medication, your healthcare provider may recommend surgery. The first choice of surgical treatment for thoracic endometriosis is often video-assisted thoracoscopic surgery (VATS). VATS is a minimally invasive surgery that involves the removal of unwanted tissue, such as endometrial lesions, from the chest cavity using a series of small incisions.
In very rare cases, a hysterectomy (surgical removal of the uterus) may be necessary to relieve severe endometriosis symptoms.
Endometriosis is often treatable, but there’s currently no known cure. All types of endometriosis—including thoracic endometriosis—can recur even after surgery or hormone therapy. However, symptoms typically resolve after the onset of menopause.
If you have trouble conceiving due to endometriosis, fertility treatments such as in vitro fertilization (IVF) may help you get pregnant.
When to Seek Care
Thoracic endometriosis is sometimes difficult to diagnose because its symptoms, including chest pain and difficulty breathing, can be easy to mistake for other conditions. It can also take some time to realize that your symptoms show up just before or during your menstrual cycle.
Reach out to a healthcare provider if your periods are painful or unpredictable, or if you’ve been having unprotected sex for 12 months or more (or six months if you’re over 35 years old) without getting pregnant. You may also have thoracic endometriosis if you notice that symptoms such as chest, neck, or shoulder pain tend to be felt on your right side.
Thoracic endometriosis is a type of endometriosis in which tissue that would normally line the uterus grows inside or around the lungs. People with thoracic endometriosis may experience symptoms like coughing, shallow breathing, and chest pain during their menstrual cycle.
As with other kinds of endometriosis, thoracic endometriosis is often treated with hormone therapy to lower estrogen production. If symptoms don’t resolve with medication, surgery may be necessary.