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Endometriosis of the Lung

Question:

I've been told that endometriosis can spread outside of the pelvic area. I even heard of a woman with endometriosis whose lung collapsed every time she had a period. Can endometriosis really spread to the lungs?

Answer:

Yes, while it is rare, endometriosis can grow in the lung. This is also known as thoracic endometriosis. There are two basic types of thoracic endometriosis: Pleural endometriosis (the lining of the lung), and parenchymal endometriosis (the lung itself). In the majority of cases, pulmonary endometriosis occurs in the pleura rather than the lung itself (the occurrence is about 5:1, pleura:parenchyma).

Pleural Endometriosis
The vast majority of patients with pleural endometriosis experience very noticeable symptoms. These include difficulty breathing (shortness of breath), pain, and pneumothorax (collapsed lung) or pleural effusion (water on the lung). Over 90 percent of cases are right-sided. It is not uncommon to find small holes in the diaphragm. The majority of patients with pleural endometriosis also have pelvic endometriosis, raising the question of whether the spread of the endometriosis happens through these small holes in the diaphragm.

Parenchymal Endometriosis
Most patients with parenchymal endometriosis cough up blood, but few have difficulty breathing or pain. Few of these patients have pelvic endometriosis, but usually have a history of pelvic surgery or vaginal delivery. The theory is that the endometrial cells spread through the blood vessels as emboli (similar to the migration of blood-clots or other foreign material).

Treatment Of Thoracic Endometriosis:
In the past, diagnosis of thoracic endometriosis has been difficult. Treatment often involved either medical suppression of the endometriosis (e.g., by prescribing Danazol or GnRH agonists ), or surgery in the form of a thoracotomy (a big incision between the ribs) and the obliteration of the pleural space (in order to prevent the lung from collapsing), without actually diagnosing or removing the endometriosis.

The patient's history plays a key role in the diagnosis of thoracic endometriosis. Traditionally, a chest x-ray or ventilation/perfusion study (a study which looks at both the air-flow and blood-flow through the lung) has helped in the diagnosis of endometriosis. MRIs can help locate and diagnose large lesions of endometriosis, but are unable to detect smaller endometriosis lesions. Thoracoscopy (laparoscopy of the thorax/pleural space) also can help diagnose and treat pleural endometriosis (greater than 80 percent of thoracic endometriosis).

Normally, when a patient undergoes general anesthesia, a breathing tube is inserted through her mouth and down the bronchus (the main breathing tube going to both lungs), and she is placed on a ventilator during the surgery. This tube is removed as she wakes up. To perform a thoracoscopy, a special double-lumen breathing tube is placed through the patient's mouth, with one tube in the right lung and one tube in the left lung. At rest a person can easily get all the air they need through one lung. The side that contains the endometriosis (let’s say the right side) is collapsed by blocking off the tube on that side, and the patient is ventilated (breathes) through the "open" tube; in this case, the left lung. The collapsed lung then opens up the pleural space, and the thorascope is introduced. The pleural cavity is inspected, and any endometriosis, scarring or fibrosis is removed. The thorascope is then removed, the incision is closed, and the lung is re-inflated. Laparoscopy should also be performed to look for endometriosis in the pelvis, abdominal cavity, diaphragm, etc.

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