What is extra pelvic endometriosis?
Extra-pelvic endometriosis is endometriosis that occurs outside the pelvis, such as in the lungs or intestines.
It happens when endometrial-like tissue implants in distant organs and responds to hormones, causing inflammation and scarring. Symptoms vary by location and may include chest pain, coughing blood, bowel pain, or cyclical swelling. Diagnosis often requires imaging, careful symptom timing, and sometimes laparoscopy or biopsy for confirmation. Treatment for extra-pelvic endometriosis may include hormonal therapy, pain management, or surgery to remove lesions.
Symptoms of extra-pelvic endometriosis
Symptoms of extra-pelvic endometriosis depend entirely on the specific organ or tissue where the lesions grow. Unlike pelvic endometriosis, pain is localized to areas like the bowel, bladder, or lungs. Bowel involvement often causes deep pain during defecation, bloating, or even rectal bleeding.
If lesions affect the urinary tract, you may experience painful urination or blood in your urine. Thoracic endometriosis can present as chest pain, shoulder pain, or shortness of breath during menstruation. Sciatic nerve involvement typically results in cyclical leg pain or numbness that mimics sciatica. Recognizing that these symptoms align with your menstrual cycle is crucial for proper diagnosis.
What causes extra-pelvic endometriosis?
The exact cause for the spread of endometriosis lesions outside the pelvic area is not clear. However, several theories explaining this phenomenon exist. These include Sampson’s theory of retrograde menstruation, hematogenic spread, lymphatic spread, and coelomic metaplasia.
Why can endometriosis appear outside the pelvis?
Medicine doesn’t have one single explanation that fits every case. Several theories are used, and more than one may be true at the same time:
- Retrograde menstruation may seed cells that implant and grow, especially on the diaphragm.
- Cell transformation (metaplasia) may allow local tissue to behave like endometrium under certain signals.
- Lymphatic or blood spread may help explain distant locations.
- Iatrogenic implantation can happen in surgical scars (for example after a C-section), where endometrial cells may be transferred to the incision site.
The “scar” pathway is one of the easiest to understand and one of the most commonly reported forms of extra-pelvic disease.
What are the types of extra-pelvic endometriosis?
Extra-pelvic endometriosis can occur in the bowels, C-section scars, diaphragm, pancreas, sciatic nerve, thorax, and umbilical cord. More appropriate terminology for endometriosis found in the thoracic cavity, umbilical, inguinal, and c-section scar is actually extra peritoneal endometriosis.
Similarly, retroperitoneal fibrotic endometriosis is proper description for recto-vaginal, for pudendal, sciatic forms of deeply infiltrating forms of advanced presentations.
Abdominal wall endometriosis
Abdominal wall endometriosis is a very rare form of extra-pelvic endometriosis. Its prevalence ranges between 0.03% and 1.5%. However, it is gaining importance nowadays due to the increasing number of Cesarean sections.
Symptoms include both cyclic and non-cyclic pain, lesion formation at the site of the C-section scar, discoloration or hyperpigmentation of the abdominal wall during menstruation, and collection of blood near the rectus abdominus muscle in some cases.
Get a Second Opinion
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 (212) 988-1444 or have your case reviewed by clicking here.
C-section scar endometriosis
C-section scar endometriosis is a rare condition in which endometriosis lesions develop at the incision site of a Caesarean section (C-section). The prevalence of C-section scar endometriosis is very low.
Symptoms of C-section scar endometriosis often take time to manifest but include both cyclical and non-cyclical pelvic pain and the development of nodules in or adjacent to the scar.
Recently, Dr. Seckin also discovered and described endometriosis in a C-section scar isthmocele.
Diaphragmatic endometriosis
Diaphragmatic endometriosis occurs in about 1-1.5% of total endometriosis diagnoses. It is largely asymptomatic. Symptoms, if present, include cyclic upper right abdominal pain under the ribs and chest pain due to stimulation of the phrenic nerve, painful breathing, and nausea.
Endometriosis of the appendix
Endometriosis of the appendix is another rare form of the disease. The involvement of the appendix in endometriosis is highly variable. It can range anywhere between 1% and 22% of cases. Symptoms overlap with those of acute appendicitis, complicating diagnosis. Other symptoms include appendiceal invaginations, abdominal colic, nausea, and black stools. Sometimes, the disease can also be asymptomatic.
Pancreatic endometriosis
Pancreatic endometriosis is another extremely rare form of extra-pelvic endometriosis. The diagnosis and treatment of pancreatic endometriosis are complex due to its extremely low prevalence. Symptoms include abdominal pain, vomiting, diarrhea, nausea, fatigue, and weight loss.
Sciatic endometriosis
Sciatic endometriosis happens when extraneous endometrial tissue start to grow around the sciatic nerve resulting in pelvic, hip, and leg pain. It shows similar symptoms to that of classical endometriosis. Additionally, it may also cause a condition known as “foot drop” that adversely affects walking ability.
Thoracic endometriosis
Thoracic endometriosis has caught a lot of attention among endometriosis specialists in recent years. It is often dubbed the next frontier in the understanding of the disease. Thoracic endometriosis can manifest as catamenial pneumothorax, hemothorax, or hemoptysis, and lung nodules.
A dual-compartment approach that helps navigate both the thorax and the pelvic regions to identify and excise all lesions is necessary to effectively treat thoracic endometriosis.
Umbilical endometriosis
Umbilical endometriosis is also rare and usually manifests as a painful swelling near the umbilicus or belly button area. This pain coincides with the monthly menstrual cycle, which is the first indication that it could be a form of endometriosis. However, this condition may also co-exist with umbilical hernias, which can cause pain even outside the menstrual cycle.
When to consult a specialist
You should consult a specialist if you experience symptoms that could indicate endometriosis, especially when they are persistent, worsening, or linked to your menstrual cycle. Severe pelvic pain, chronic chest or shoulder pain during menstruation, breathing difficulties, or unusual bleeding patterns are all signs that require professional evaluation. These symptoms may be related to endometriosis or another underlying condition that needs timely diagnosis.
If you have already been diagnosed with endometriosis but notice new symptoms, such as pain in areas outside the pelvis, changes in menstrual flow, or difficulty breathing during your period, a follow-up with a specialist is important. Early intervention can help prevent complications and may improve treatment outcomes.
Consulting a specialist is also recommended when symptoms interfere with daily life, impact fertility, or do not improve with basic pain management. A thorough assessment can lead to a targeted treatment plan that addresses both symptom relief and long-term health. Regular check-ups and open communication with your healthcare provider are key to managing endometriosis effectively.
How is extra-pelvic endometriosis diagnosed?
Diagnosis usually starts with history: symptoms, their timing, prior surgeries, fertility history, and response to hormonal medications.
Then imaging and specialty evaluation come into play:
- Ultrasound may help for pelvic disease and sometimes abdominal wall lesions.
- MRI can be useful for deep disease mapping depending on the site.
- CT / chest imaging may show pneumothorax or lung findings if thoracic disease is suspected.
- Surgical evaluation (laparoscopy, thoracoscopy/VATS) may be needed for confirmation and treatment planning in certain cases.
A key point from patient-focused guidance: blood biomarkers such as CA-125 are not recommended as a diagnostic test for endometriosis.
How to treat extra-pelvic endometriosis treated?
Surgical treatment that includes laparoscopic deep excision surgery combined with cold excision is the definitive way to identify and excise all endometriosis lesions. Since these lesions occur outside the pelvic area, a multi-disciplinary approach is necessary to preserve the function of the affected organs and ensure improved quality of life.
Your doctor may prescribe non-steroidal anti-inflammatory drugs (NSAIDs) for symptomatic pain relief and recommend the use of progestin-only contraceptives or GnRH antagonists to reduce symptoms. However, none of these treat the underlying cause of the disease.
Hysterectomy may be necessary in some cases, but we do not recommend it unless there is no other alternative and the patient fully understands that it can lead to surgical infertility.
Frequently Asked Questions
Can endometriosis really be found in the lungs?
Yes, endometriosis can be found in the lungs and on the pleura lining the chest cavity. This condition is called Thoracic Endometriosis Syndrome. It can cause chest pain, shortness of breath, and in severe cases, a lung collapse (pneumothorax) during menstruation.
Is extra pelvic endometriosis harder to diagnose than pelvic endometriosis?
Yes, it is generally much harder to diagnose because the symptoms mimic other organ specific diseases. Doctors often look for lung or bowel issues first without considering a gynecological cause. Furthermore, standard pelvic ultrasounds will not show lesions in the chest or on nerves, leading to many “normal” test results.
Can I have extra pelvic endometriosis without having pelvic pain?
While rare, it is possible to have significant extra pelvic symptoms with minimal or manageable pelvic pain. Some patients present with lung collapses or sciatica as their primary complaint. However, most patients with extra pelvic disease also have some degree of pelvic endometriosis, even if it has not been diagnosed yet.
Does a hysterectomy cure extra pelvic endometriosis?
No, a hysterectomy removes the uterus but does not remove endometriosis lesions located elsewhere in the body. If lesions remain on the lungs, bowel, or nerves, they can continue to respond to remaining hormones (produced by ovaries or hormone replacement) and cause symptoms. Excision of the lesions is required.
How is sciatic endometriosis treated?
Sciatic endometriosis requires specialized laparoscopic surgery to decompress the nerve. A surgeon trained in neuropelviology must carefully shave or cut the endometriosis tissue off the nerve sheath. Hormonal therapy may be used to shrink the tissue temporarily, but surgery is usually needed to prevent permanent nerve damage.
Is extra-pelvic endometriosis rare?
It’s considered less common than pelvic endometriosis, but “rare” can be misleading: thoracic and scar-related disease are likely underdiagnosed because symptoms mimic other conditions and many clinicians don’t immediately connect them to the menstrual cycle. Systematic reviews have emphasized that extrapelvic and distant disease has been reported across a considerable number of studies, suggesting it may be more recognized now than in the past.
Can imaging confirm extra-pelvic endometriosis?
Imaging can be very helpful, but it’s not always definitive. A scan might show a lung collapse, a scar mass, or deep infiltrating disease patterns, yet endometriosis can still be missed. The strongest diagnostic “signal” often comes from the combination of symptom timing, exam findings, imaging, and (in selected cases) surgical visualization and histology.
Get a Second Opinion
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.