Extra-pelvic endometriosis

Endometriosis is the growth of tissue resembling the lining of the uterus in other parts of the body. This usually happens in the pelvic region. However, although rare, these lesions can also spread to other parts of the body and cause extra-pelvic endometriosis. 

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.

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.

Bowel endometriosis

Bowel endometriosis usually affects the anterior part of the rectum and peritoneal layers and is one of the most common yet often ignored forms of the disease. The peritoneum is now considered to be an important organ with key immune and secretory functions and not just as an abdominal lining. 

Bowel endometriosis can affect the peritoneal layers, the cul-de-sac, rectum, perirectal area, colon, and intestines. These lesions can be multi-focal (within the same area) or multi-centered (spread diffusely).

Symptoms include painful bowel movements, bloody stools, abdominal bloating, diarrhea, constipation, and painful intercourse that get worse during periods.

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. 

How to diagnose extra-pelvic endometriosis?

The low prevalence of extra-pelvic endometriosis makes diagnosis complicated. Laparoscopic deep excision surgery followed by histological examination is the only “gold standard” for confirming any form of endometriosis. 

Depending on the type of extra-pelvic endometriosis, non-invasive techniques that afford a fair degree of reliability and sensitivity include magnetic resonance imaging (MRI), computerized tomography (CT), and other tests specific to the affected organ. 

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.