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This chapter should be cited as follows:
El-Zibdeh A, Arambage K, et al, Glob. libr. women's med.,
ISSN: 1756-2228; DOI 10.3843/GLOWM.417723

The Continuous Textbook of Women’s Medicine SeriesGynecology Module

Volume 3


Volume Editors: Professsor Andrew Horne, University of Edinburgh, UK
Dr Lucy Whitaker, University of Edinburgh, UK


Extra-Pelvic Endometriosis

First published: November 2023

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By completing 4 multiple-choice questions (randomly selected) after studying this chapter readers can qualify for Continuing Professional Development awards from FIGO plus a Study Completion Certificate from GLOWM
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Extra-pelvic endometriosis refers to endometrial glands and stroma present in locations outside the pelvis, in a distant site from gynecological organs.1,2

The true prevalence of extra-pelvic endometriosis is unknown but is believed to range between 1 and 12% of patients with pelvic endometriosis.2 Endometriosis can appear at any organ and has the unique ability to maintain its functionality in distant locations away from the genital organs. Catamenial extra-pelvic symptoms associated with a person’s menstrual cycle should trigger a high degree of suspicion for endometriosis regardless of anatomic location.

The main objective of this chapter is to summarize the clinical presentation, pathogenesis, diagnostic tools, treatment modalities, and outcomes amongst common sites of extra-pelvic endometriosis. Extra-pelvis endometriosis has been categorized in this chapter to reflect different subtypes of endometriosis based on etiology and pathogenesis.

Objectives of this chapter are as follows:

  • Describe the etiology and pathogenesis of extra-pelvic endometriosis.
  • Outline presentation and diagnosis of extra-pelvic endometriosis.
  • Review the treatment options and recurrence rate of extra-pelvic endometriosis.
  • Describe reported malignant transformation of extra-pelvic endometriosis.


Cutaneous endometriosis describes the presence of endometrial-like tissue in the skin or fascial layers immediately deeper to the skin, usually affecting the cutaneous layers of the abdominal wall.3 It can be divided into primary cutaneous endometriosis and secondary cutaneous endometriosis.4 Primary cutaneous occurs spontaneously without previous history of surgery, while secondary cutaneous or scar endometriosis is assumed to arise from seeding and implantation of endometrial glands or stroma following abdominal or pelvic surgery.5


Secondary cutaneous endometriosis on the abdominal wall is considered one of the most common sites for extra-pelvic endometriotic implants.6,7 The prevalence of abdominal wall cutaneous endometriosis has been estimated to be around 5% of people with extra-pelvic endometriosis,8 and has the lowest association to disease elsewhere with approximately 18% of patients having co-existent pelvic endometriosis.5,9,10 Cesarean section scars are the most common site of secondary extra-pelvic cutaneous endometriosis.10


The commonest theory suggests that endometrial cells are mechanically seeded into the cutaneous wall facia or surrounding subcutaneous tissues along the tract of surgical incision wound at the time of an index surgery including cesarean sections, myomectomy, tubal ligation, or hysterectomy. It may also occur within the laparoscopic port site incisions during laparoscopic excision of pelvic endometriosis or morcellation procedures. It is likely that exposed endometrial tissues bind to the fibrinous surface of incisional scars, while the endometriotic angiogenic properties and continued hormonal stimulation provide implant viability and resultant symptoms.

Scar endometriosis is commonly confined to the superficial layers of the abdominal wall or pelvis; however, it may infiltrate into deeper layers into the rectus abdominus muscles or rectus sheath fascia.


This commonly manifests as a painful abdominal mass within proximity to the incision line. Pain and swelling of the mass are frequently cyclical but can also be constant and non-cyclical in nature.9,11 On clinical examination, a palpable subcutaneous mass around the surgical scar may be identified, this mass may be more pronounced and increasingly tender if assessed during ovulation or menstruation.


Imaging with ultrasonography, computed tomography (CT), or magnetic resonance imagining (MRI) may be considered. Ultrasound scan (US) is the most widely used initial investigation although features of scar endometriomas at US are non-specific and may vary in nature. Lesions may be single, multiple, multi-cystic, solid, or mixed in nature. Descriptive appearances commonly include a heterogeneous hypoechoic mass with echogenic spots or thick echogenic strands representing the largely fibrotic component. Most scar lesions demonstrate vascularity at color Doppler US,12 and the distribution of hemorrhagic or fibrotic foci on the scan are related to the amount and distribution of glands to stroma within the cutaneous lesion.13

The use of MRI and CT scans can characterize the extent of the lesion, fascial attachment, and deeper invasion and therefore, can be useful for preoperative preparation. Those lesions involving the rectus sheath may require input from reconstructive abdominal wall surgeons necessitating the use of mesh to repair large sheath defects. Cutaneous scar endometriotic lesions on MRI show iso- or high signal intensity compared with the muscle on both T2- and T1-weighted sequences. The hyperintense foci on T1-weighted images with fat suppression are due to small hemorrhages, however, the absence of hemorrhagic foci may be caused by hormonal treatment.14 Fine needle aspiration cytology (FNAC) has been described by some authors as a fast and accurate method to establish the diagnosis and rule out malignancy prior to surgery.15 Cytology commonly reveals hemorrhage with hemosiderin-laden macrophages and sheets of epithelial and stromal cells.16 However, in a recent systemic review, only 66.7% of FNAC confirmed endometriosis in cytology samples.11 The possibility of spread along the course of the needle in FNAC should be taken into consideration, therefore, it is advisable to include the site of aspiration in the surgical excision.

Differential diagnosis includes abdominal wall masses, such as hernias, lipomas, sebaceous cysts hematomas, and soft tissue malignant tumors.17

Treatment and prognosis

The use of widely recognized hormone treatments may be useful to control symptoms although recurrence with the discontinuation of hormone treatment is common.18

For those where medical treatments are not suitable or acceptable, surgical excision should be considered.11 Full excision of the endometriotic lesion with disease free tissue margins is associated with a very high cure rate with a recurrence rate estimated at 5%. This is considerably lower than the recurrence rate of ovarian endometrioma and may in part be due to separate etiologies.11

A multi-disciplinary approach is recommended and involvement of plastic or general surgeons may be considered to achieve surgical excision with disease-free margins. This may, in large fascial defects, require repair with biologic or synthetic surgical mesh.19 In circumstances where the nodule is below the rectus sheath, laparoscopic excision may be offered.


Vulvo-perineal endometriosis is a rare subtype of extra-pelvic endometriosis characterized by endometrial glands and stroma present in perineal lacerations, episiotomy scars, or Bartholin gland excision sites.


Perineal endometriosis has been described in 0.17–0.37% of people with endometriosis,20,21 It is most often associated with previous episiotomy, obstetrical lacerations, vulvo-vaginal surgery, or trauma. The median latent period between the time of perineal trauma or surgery and occurrence of symptoms is 2.5 years, ranging from 1 month to 14 years.20 Primary perineal endometriosis has been described as well and contributes 5% of all patients with perineal endometriosis.20


Direct mechanical implantation of endometrial glands during delivery into perineal lacerations or scars appears to be the most widely accepted theory. Different theories can explain spontaneous perineal endometriosis, including lymphovascular dissemination from the round ligament into the labia majora, or coelomic metaplasia in cases of Bartholin cyst endometriosis.22


The main symptoms of vulvo-perineal endometriosis are cyclical pain and swelling; lesions may invade the anal sphincter and cause variable degrees of bowel symptoms. It is important to obtain a detailed medical history and perform a thorough clinical examination with digital rectal examination to assess for anal sphincter involvement. The combination of a palpable perineal nodule in proximity to a scar, accompanied by cyclical pain and swelling in reproductive age patients is highly suggestive of vulvo-perineal endometriosis.23,24,25


Perineal and endoanal ultrasound as well as MRI help to precisely describe the lesions and to assess the extent of anal sphincter involvement. The presentation of vulvo-perineal endometriosis on ultrasound examination could be irregular hypoechoic without blood flow signal, or a cystic structure within the perineum with clear border and surrounding vascularity.24

Treatment and prognosis

Symptomatic relief may be achieved using commonly recognized hormonal treatments. However, complete surgical excision is associated with less recurrence and a high likelihood of cure.24,25 Complete excision is recommended with free surgical margins to reduce recurrence.26 When the anal sphincter is involved, wide excision of the endometrial tissues with a good healthy margin and primary sphincteroplasty may be required.20 Collaboration between gynecologist and colorectal surgeon is recommended as risks include incontinence following surgery involving the anal sphincter. In contrast, patients closer to menopause may be treated optimally with a narrow excision avoiding the anal sphincter and the risks associated. Recurrence of perineal endometriosis is low and has been described in 10% of cases.27


Primary umbilical endometriosis or Villar’s nodule occurs when endometrial glands or stroma are present within the umbilicus without previous history of surgery. Unlike other abdominal wall endometriosis, Villar’s umbilical nodule appears to be primary in nature in most cases.7 It should be differentiated from cutaneous scar endometriosis in umbilical incision scars described above.


Primary umbilical endometriosis was first described by Villar in 1886, it is considered a rare entity that affects 0.5–0.1% of all people with extra-pelvic endometriosis.28 The average duration of symptoms prior to presentation is usually over a year, with a mean age of presentation of 37.7 years.29 this may reflect the need for prolonged exposure to menstrual, metaplastic, or environmental factors leading to the development of primary umbilical endometriosis.


The exact pathophysiology is not clearly understood, and it is unlikely that a single theory adequately explains primary umbilical endometriosis. There are two that carry plausible explanation: “metastasis theory” and “metaplasia theory”. The metastatic theory suggests either lymphatic or hematogenous metastasis of ectopic endometrial cells into the umbilicus. The metaplasia theory suggests metaplastic changes within celomic mesothelial tissues within the peritoneum result following a specific stimulus, such as hormones, trauma, and/or inflammatory factors.30,31


The typical clinical presentation of umbilical endometriosis is discrete single or multiple, popular, nodular, or cystic lesions with discoloration either bluish, violaceous, or pink. The color and shape of these lesions depends on the amount of hemorrhage and the depth of penetration of ectopic endometrial tissue. These lesions typically enlarge, become more painful or bleed concomitantly with menstruation. Differential diagnosis should include malignancies, in particular melanoma and umbilical metastasis of visceral carcinoma (Sister Mary Joseph nodule) along with pyogenic granuloma, hernia, and pemphigus vegetans.32


Similar to scar endometriosis, ultrasonography can be useful in describing characteristic hypoechoic lesions with mixed echogenicity. MRI has been reported to be efficient in detailed characterization of these lesions with the depth of invasion into surrounding tissues.33 Transvaginal ultrasound and pelvic MRI may be considered amongst patients not previously known to have pelvic endometriosis.

Management and prognosis

Management of umbilical endometriosis has not been standardized due to paucity of cases. Medical management using hormone therapy has been described to reduce the size of umbilical lesions and ameliorate associated swelling and pain.34


Inguinal endometriosis occurs in several different forms, including cystic endometriomas within the hernia sac and canal of Nuck, and solid mass lesions in the extra-pelvic portion of the round ligament and its insertion into subcutaneous tissues.35,36 The canal of Nuck represents the anatomical defect when parietal peritoneal pouch follows the gubernaculum during embryological development. The female gubernaculum extends proximally from the round ligament attachment to the uterus into the abdominal wall, running through the inguinal canal into its variable subcutaneous attachment between the internal inguinal ring and the fascia under the pubic bone. Failure of closure of this peritoneal defect may present as an indirect hernia.37


Inguinal endometriosis is a rare form of extra-pelvic endometriosis; it has been described in 0.6% of people with endometriosis38 with a higher average age at diagnosis of 37 years old.7,36


The pathogenesis of inguinal endometriosis remains unclear. More than 80% of inguinal endometriosis occurs at the right inguinal region.38 This can be explained by retrograde menstruation theory with reflux of menstrual blood into the pelvis, and consequent circulation through peritoneal fluid in a clockwise fashion, in the presence of the sigmoid colon blocking the left inguinal ring, allows more of the peritoneal fluid with endometrial cells to pool at the right inguinal ring. Lymphatic spread from the uterus through lymphatic vessels along the round ligament was a suggested theory, however this does not explain the predominance of inguinal endometriosis in the right groin.39,40


The presentation is a commonly cyclical enlargement of a painful inguinal mass. Patients may initially present to the general surgeons and these lesions can be misdiagnosed as a typical inguinal hernia or a canal of Nuck hydrocele.41


Ultrasound scan is widely used to assess inguinal pathology; inguinal endometriosis appears as hypoechoic cystic lesions with internal echoes. MRI, in particular T1 weighted imaging, is helpful in preoperative diagnosis of inguinal endometriosis as these lesions typically appear hyperintense on T1 weighted images.7 Diagnosis may only be achieved at time of surgery as the final diagnosis is based on histopathological and immunohistochemistry confirmation.

Treatment and prognosis

Most authors recommend surgical resection of these inguinal lesions (laparoscopic or open) and closure of the internal inguinal defect with or without mesh.41,42,43 Further excision of disease extensions into the round ligament, labia majora, or vulva may be considered but balanced against increasing surgical morbidity. Surgical excision can be challenging as inguinal endometriosis is located close to iliac, inferior epigastric, and femoral vessels. Postoperative recurrence rates appear to range from 6–16%.41,42,43

The use of hormonal treatment particularly Dienogest has been shown to improve groin pain and may be an option for people who do not want primary surgery or reoperation after recurrence.7 Postoperative hormone treatment may also be considered to reduce recurrence after surgical treatment.42,43


Extra-pelvic endometriosis has been reported to affect all abdominopelvic viscera, including liver, kidneys, pancreas, and biliary tract. The median age of patients with visceral endometriosis is approximately 40 years.7 The pathogenesis of visceral endometriosis may be explained by retrograde menstruation and direct transmission of endometrial cells with circulating peritoneal fluids, also lymphovascular spread offers a plausible explanation for distant upper abdominal or retroperitoneal endometriosis of the kidney.

Patients may present with upper abdominal pain with an abdominal mass, liver failure amongst those with liver endometriosis; flank pain, hematuria, and pyelonephritis with kidney endometriosis; epigastric pain and pancreatitis with pancreatic endometriosis.10

CT scan is commonly used to aid the diagnosis in patients presenting with abdominal pain, CT images can vary but usually show cystic lesions on or within visceral abdominal organs that are either simple or complex, with mixed density, with or without contrast uptake.44,45,46 Fine Needle Aspiration may be used to establish a diagnosis; however, diagnosis may only be established at time of surgery or by histopathology and immunohistochemistry,47 like other extra-pelvic endometriosis.48

Treatment for visceral endometriosis is mainly surgical, relying heavily on a multidisciplinary approach with specialized hepatobiliary or upper GI surgeon involvement. Patients may require conservative surgical procedures like local resection, drainage or partial hepatectomy or nephrectomy,49 while more radical procedures may be needed depending on the severity of organ involvement.50


Thoracic endometriosis is characterized by the presence of endometriosis within the thoracic cavity, which includes the diaphragm, pleural surfaces, and lung parenchyma.47,51 Thoracic endometriosis (TE) is one of the commonest forms of extra-pelvis endometriosis and is associated with important clinical ramifications.


Epidemiological studies have shown an older age of presentation compared to pelvic endometriosis, with the mean age of presentation of TE to be 34–37 years.52 Approximately 50–80% of patients have concomitant pelvic endometriosis and have suffered with pelvic symptoms for approximately 7 years before developing TE symptoms.53 The thoracic diaphragm and the visceral diaphragm are the most common sites of TE lesions (38.8% and 29.6%, respectively).53


The pathogenesis of thoracic endometriosis is not yet fully understood. The most prominent theory to explain TE is Sampson’s retrograde menstruation where circulated peritoneal fluid with effluxed endometrial cells follows a distant pattern of movement; peritoneal fluid flows from the pelvis into the right hemidiaphragm deviating away from the left hemidiaphragm due to obstruction by falciform ligament and phrenocolic ligament. Endometrial cells are thought to implant on the diaphragmatic surface or undergo transperitoneal-transdiaphragmatic migration to the pleural cavity via congenital or acquired fenestrations within the diaphragm.54 The fact that most TE occurs predominantly on the right side supports this migration theory.51,54 A similar right-sided preponderance is seen in Meigs syndrome where ascitic fluid associated with ovarian tumors transudates into the pleura, particularly the right side.55 Coelomic metaplasia theory proposed that endometriotic cells arise by metaplasia of the mesothelial cells of pleura or visceral diaphragm; this theory cannot explain the right-sided predominance either. Lymphatic and vascular dissemination theory into thoracic cavity and lung parenchyma, however this theory also fails to explain right-sided predominance but can explain lung parenchymal endometriosis that present with non-catamenial hemoptysis.


Patients may present with chest or shoulder pain or upper abdominal pain, as well as presenting with catamenial pulmonary symptoms secondary to diaphragmatic, pleural or lung parenchymal endometriotic lesions. The clinical signs of thoracic endometriosis include catamenial and non-catamenial pneumothorax, hemothorax, hemoptysis, and lung nodules.56

Catamenial pneumothorax is defined as two episodes of pneumothorax temporally related to the onset of menses, usually within 72 hours. 20–25% of spontaneous pneumothorax in reproductive aged women are reported to be CP.54 The most common symptoms associated with catamenial pneumothorax are shortness of breath, cough, and pleurisy. Other symptoms associated with thoracic endometriosis include chest pain, shoulder pain with scapular or cervical radiation because of phrenic nerve involvement.51,53,54,56

It is not well understood how air enters the thoracic cavity and creates pneumothorax. Several theories have been suggested; the first theory suggests a trans-diaphragmatic air passage through diaphragmatic defects, the air originates from air entering the peritoneal cavity through the uterus and fallopian tubes during menses. The second theory is pulmonary endometriosis may cause perforation of alveoli and subsequent air leak. Finally, the prostaglandin theory, specifically Prostaglandin F2a, increases during menstruation, which may cause vasoconstriction, bronchospasm, and subsequent alveolar rupture.7,52


Various diagnostic tests can be utilized to achieve a diagnosis of TE, this includes chest radiographs, chest CT scan, MRI, video-assisted thoracoscopic surgery (VATS), and bronchoscopy. CT can be considered following an initial diagnosis of pneumothorax as it is readily available and inexpensive, however this modality is not sensitive or specific for TE. While CT scan can be a valuable tool for identifying pneumothorax other chest pathology, the radiation risk associated with breast cancer, particularly in young patients should be carefully considered.57,58

The use of MRI has been reported to be superior to CT scan in diagnosing diaphragmatic, pleural, and hemorrhagic lesions with overall sensitivity of 83%.59 The gold standard for diagnosing pleural or full thickness diaphragmatic TE is video-assisted thoracoscopic surgery (VATS).47 This enables whole intrathoracic exploration, including the parietal and visceral pleura, lung and thoracic side of the diaphragm. The use of VATS also provides means for treatment including surgical excision or cauterization of lesions.47 Diagnosis of TE is confirmed by histopathology or positive immunohistochemistry markers specific for endometriosis.

Treatment and prognosis

Treatment can be challenging without robust data to support one strategy over another. Common approaches include hormonal suppression with continuous contraceptives or progesterone only treatment, Dienogest has been described by several authors for the treatment of TE.60,61,62 Alternatively, gonadotropin-releasing hormone (GnRH) agonists are used as initial line treatment aiming at complete suppression of ovarian steroid hormone production. This continuous hormone suppression may result in cessation of menstrual bleeding and reduction of the frequency of catamenial symptoms. The duration of use of these medications is influenced by their side effects and tolerability by the patient. Discontinuation of hormone treatment is associated with 50% symptom recurrence rate.7 It is important to consider surgery in patients with refractory or recurrent disease under hormone therapy.63 Several studies suggested the use of postoperative hormone suppression to reduce the risk of recurrence in line with the management of pelvic disease.60,61,62,63

Pulmonary superficial endometriotic implants can be treated using bipolar diathermy, CO2 laser, Nd-YAG laser, or others, while deeper lesions are more commonly excised.64 In the case of lung parenchymal lesions, wedge resection, subsegmentectomy, or lobectomy has been described as effective surgical approaches.47,60 Less invasive treatments including pleurodesis are described offering an alternative treatment for recurrent pneumothorax with or without concurrent surgical excision.65 Pelvic and thoracic endometriosis are often concomitant requiring a coordinated multidisciplinary approach to treat both in either a single or two stage procedure. Surgical treatment for pelvic and thoracic endometriosis often involves two separate procedures, which can increase healthcare costs, and may reduce patient satisfaction. However, combining VATS and traditional laparoscopy through a multidisciplinary approach can be an alternative optimal way to simultaneously treat pelvic, diaphragmatic, and thoracic endometriosis in a single surgical procedure.60

For diaphragmatic lesions, visceral (abdominal) laparoscopy can reveal endometriotic implants that may appear as black, blue, or red lesions. There is a significant variation in the appearances of diaphragmatic endometriosis, and some reported vesicular lesions or peri-hepatic adhesions. Laparoscopic or robotic excision of lesions with the use of synthetic mesh has been recommended to close larger diaphragmatic defects. Combined VATS and laparoscopy can be utilized to achieve surgical excision of full thickness diaphragmatic lesions. Operative complications reported include pneumothorax and haemothorax, prolonged air leak, pleural effusion, vascular injury to the superior vena cava, diaphragmatic paralysis secondary to phrenic nerve injury, Horner’s syndrome, and diaphragmatic hernia.66

The recurrence rate of thoracic endometriosis has been reported to be 14.3–46.7% over the 12-month follow-up period.65


Rare sites of endometriosis have been described in the literature; this includes the central nervous system, upper and lower gastrointestinal tract, upper renal tract and extra-pelvic muscles and peripheral nerves. In cases of the central nervous system, symptoms may include cyclic seizures, hemiparaesthesia, and cyclic headache. In cases of conus medullaris endometriosis, patients also presented with urinary and bowel dysfunction.6,7 Motor dysfunction has also been described for patients with peripheral nervous endometriosis. Hormone treatment is usually utilized for central nervous system endometriosis while adjuvant hormone treatment and surgical excision has been described for endometriosis affecting the peripheral nervous or extra-pelvic muscles.6


Malignant transformation of endometriosis is reported at around 1%.67 Malignant transformation of abdominal wall cutaneous/scar endometriosis was reported to carry very poor prognosis.68 Clear cell carcinoma and endometrioid carcinoma are the most common types and have been reported in 66.7% and 14.6%, respectively.10 Malignant transformation involves several genetic, immunological, and environmental factors.

Malignant evolutions of abdominal wall endometriosis appear to occur most frequently with cesarean section scar endometriosis.69 The treatment of endometriosis-associated abdominal wall malignancies is surgical wide excision along adjuvant chemotherapy/radiotherapy.70

Overall, there is paucity of reports describing the malignant transformation of extra-pelvic endometriotic lesions, therefore, malignancy should be suspected in recurring or rapidly enlarging lesions to avoid delayed diagnosis and intervention.


There is increasing awareness of the burden extra-pelvic endometriosis may pose. This entity remains enigmatic with varying clinical presentations and unclear pathogenesis. Due to unfamiliarity and heterogeneity of presentation of these uncommon conditions, patients often get referred to specialties inexperienced with managing endometriosis. This may further delay diagnosis. It is essential that clinicians assess patients comprehensively where there is pain associated with menstruation, whether this is pelvic or extra-pelvic in origin. Comprehensive evaluation of patients’ history should be performed in tandem with imaging and individualized diagnostic and therapeutic strategies should be sought.

To date, there is not enough evidence available comparing surgical with medical treatment to indicate the potential superiority of one of them over the other. Hormone treatment may be effective in managing symptoms, but symptoms commonly reoccur when hormone suppression is discontinued. Definitive diagnosis is achieved through histologic confirmation of the excised specimens. Patients with suspected extra-pelvic endometriosis require specialized input and centralized care within a multidisciplinary team. The benefits of centralized care are multiple: (1) allowing centers to develop expertise with sufficient case numbers; (2) patient safety improves with increasing experience of managing complex surgical cases; and (3) establishment of a research infrastructure to enable prospective collection of data evaluating efficacy of different interventions to help guide practice nationally and internationally.


  • While endometriosis commonly affects pelvic organs, it should be suspected in extra-pelvic sites in patients presenting with cyclical or catamenial symptoms.
  • In addition to detailed history and physical examination, the use of imaging, such as ultrasonography, CT, and MRI scans, can aid in establishing the diagnosis of endometriosis in extra-pelvic sites.
  • Treatment of extra-pelvic endometriosis includes hormone suppression to relieve symptoms and reduce recurrence as well as wide surgical excision of lesions when appropriate.
  • A multidisciplinary approach involving specialists in other fields where extra-pelvic endometriotic lesions are present is necessary to tailor the best management for patients with extra-pelvic endometriosis.
  • Malignant transformation of extra-pelvic endometriotic lesions has been described in the literature and should be excluded in recurring or rapidly enlarging lesions despite treatment.


The author(s) of this chapter declare that they have no interests that conflict with the contents of the chapter.



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