Imaging of gastrointestinal endometriosis: what the radiologist should know

Bowel Endometriosis: Systematic Approach to Diagnosis with US and MRI

Endometriosis involving the bowel is a severe form of the disease, and the bowel is the most common site of extragenital endometriosis. Surface lesions of the bowel are considered peritoneal disease. Bowel endometriosis (BE) is defined as endometriotic tissue infiltrating the muscularis propria layer of the bowel wall. BE is estimated to affect up to 37% of patients with known deep endometriosis, highlighting its coexistence with genital endometriosis. The rectosigmoid colon is the most common segment of the bowel involved, followed by the distal small bowel. US and MRI are the most common imaging modalities used to detect BE. Depending on which bowel segment is imaged, endometriosis protocols for transvaginal US after bowel preparation with a transabdominal component and MRI and MR enterography are most commonly used. The authors provide a systematic approach to the diagnosis of BE using these imaging modalities. Imaging protocols and techniques for optimization of visualization of the bowel are discussed, the normal bowel wall anatomy with both imaging modalities is described, and the varying degrees of bowel wall involvement in endometriosis are illustrated. The imaging features of infiltration of endometriosis in the bowel muscularis propria are described in detail, along with key imaging findings to be conveyed to surgical colleagues to optimize surgical treatment and decrease complications, thereby improving overall patient outcomes. ©RSNA, 2025 Supplemental material is available for this article.

Intestinal endometriosis amongst other extra-pelvic endometriosis foci presenting as acute/subacute bowel obstruction in women of reproductive age: a retrospective case series study

BACKGROUND

This study aimed to investigate the prevalence and clinicopathological correlates of intestinal endometriosis, amongst other extra-pelvic endometriosis foci, presenting as bowel obstruction in general surgery practice.

METHODS

A total of 23 female patients (mean ± SD age: 34.9 ± 6.5 years) who underwent abdominal surgery for acute bowel obstruction and received histopathological diagnosis of endometriosis were included in this retrospective case-series study. Data on patient characteristics, obstetric history, preoperative laboratory and imaging findings, preoperative provisional diagnosis, type of surgical intervention and the pathological diagnosis, and postoperative outcomes were recorded.

RESULTS

Definitive diagnoses on histopathological work-up involved intestinal endometriosis (52.2%), scar endometriosis (26.0%), ovarian endometriosis (13.0%) and inguinal endometriosis (8.7%). Postoperative complication, reoperation and recurrence rates were 8.7%, 8.7%, and 13.0%, respectively. Intestinal endometriosis, when compared to other extra-pelvic endometriosis foci (scar and inguinal), was associated with significantly higher preoperative platelet counts (332.0(284.0-528.0)vs. 239.0(223.0-370.0) 103/µL, p = 0.010), lower albumin levels (4.0(2.7-4.7) vs. 4.5(4.2-4.9) g/dL, p = 0.029), higher rates of preoperative CT utilization (91.7% vs. 0.0%, p < 0.001) and emergent surgery (83.3% vs. 0.0%, p = 0.001) and longer LOS (median 4.5 (1.0-26.0) vs. 1.0(1.0-1.0) days, p = 0.001) along with a non-significant tendency for higher postoperative complication (16.7% vs. 0.0%) and ICU stay (25.0% vs. 0.0%) rates.

CONCLUSION

Our findings revealed intestinal endometriosis, predominantly in the terminal ileum/appendix, was the most common extra-pelvic cause of acute bowel obstruction. The scar endometriosis, inguinal endometriosis and ovarian endometriosis appeared to be other potential but less prevalent aetiologies in this setting.

Acute appendicitis due to appendiceal endometriosis: Two case report and literature review

INTRODUCTION

Appendiceal endometriosis (AE) is a rare condition, with a prevalence ranging from 0.05 % to 1.7 % in patients with endometriosis. It represents <1 % of cases of acute appendicitis (AA).

CASES PRESENTATION

We present two cases of AA where the histological cause was endometriosis. Both cases involved patients around 40 years old who presented with abdominal pain in the right iliac fossa. AA was diagnosed through abdominal computed tomography (CT), which in the first case showed acute appendicitis, successfully treated with laparoscopic appendectomy. In the second case, the CT showed signs of an appendiceal phlegmon, initially treated non-operatively with poor response, leading to exploratory laparoscopy and abscess drainage 48 h later. Subsequently, a scheduled laparoscopic appendectomy was performed after 6 months. Histopathological diagnosis in both cases was AA due to AE with endometrial glands showing recent bleeding, causing hyperplasia of the appendiceal muscular layer.

DISCUSSION

Endometriosis, characterized by the presence of endometrial tissue outside the uterine cavity, can rarely affect the appendix, termed AE. AE, though uncommon, poses diagnostic challenges due to nonspecific imaging findings and variable presentations, ranging from asymptomatic cases to AA. Histological evaluation post-appendectomy is definitive for diagnosis. AE is associated with right-sided pelvic involvement and often requires surgical management, with appendectomy typically resolving acute symptoms. However, recurrence of cyclical pain due to pelvic endometriosis may persist, underscoring the importance of comprehensive evaluation during laparoscopic procedures.

CONCLUSION

AA caused by AE is an uncommon condition, with very difficult preoperative diagnosis based solely on personal history, clinical presentation, and even imaging studies. It should be considered in differential diagnoses for women of reproductive age with associated pelvic endometriosis, although the recommended treatment in all cases is surgical.

A Gender Perspective on Coloproctological Diseases: A Narrative Review on Female Disorders

Coloproctological diseases, including both benign and malignant conditions, are among the most common diagnoses in clinical practice. Several disorders affect both men and women, while others are unique to women, or women are at a greater risk of developing them. This is due to anatomical, biological, and social conditions and also due to females' exclusive capabilities of reproduction and pregnancy. In this context, the same proctological disease could differ between men and women, who can experience different perceptions of health and sickness. There is a raised awareness about the impact of different diseases in women and a growing need for a personalized approach to women's health. In this review, we aim to summarize the specific features of the main coloproctological diseases, specifically in the female population. This includes common complaints during pregnancy, conditions linked to vaginal delivery, functional consequences after colorectal resections, and conditions presenting a gender disposition.

Endometriosis, a common but enigmatic disease with many faces: current concept of pathophysiology, and diagnostic strategy

Endometriosis is a benign, common, but controversial disease due to its enigmatic etiopathogenesis and biological behavior. Recent studies suggest multiple genetic, and environmental factors may affect its onset and development. Genomic analysis revealed the presence of cancer-associated gene mutations, which may reflect the neoplastic aspect of endometriosis. The management has changed dramatically with the development of fertility-preserving, minimally invasive therapies. Diagnostic strategies based on these recent basic and clinical findings are reviewed. With a focus on the presentation of clinical cases, we discuss the imaging manifestations of endometriomas, deep endometriosis, less common site and rare site endometriosis, various complications, endometriosis-associated tumor-like lesions, and malignant transformation, with pathophysiologic conditions.

Endometriosis MRI: Atypical cases, pitfalls and mimics

Endometriosis is a common but often underdiagnosed chronic gynaecological disease. Endometriosis mimics other diagnoses both clinically and radiographically, presenting a diagnostic challenge. Endometriosis can be categorised as superficial pelvic endometriosis, deep invasive endometriosis (DIE) or endometrioma. Endometrioma and DIE, including polypoid endometriosis, can masquerade as invasive neoplasms. Endometriosis can be misdiagnosed in less common locations or during pregnancy. Ultrasound is the initial investigation for endometriosis; however, MRI is advantageous in providing a larger field of view for increased detection of nodules as well as distinguishing malignancy with greater certainty. This review highlights endometriosis mimics, pitfalls and atypical cases on MRI.

Nodular image in the appendix observed on ultrasound: endometriosis or neuroendocrine neoplasia?

Objective

To evaluate the association between clinical and imaging with surgical and pathological findings in patients with suspected neuroendocrine tumor of appendix and/or appendix endometriosis.

Methods

Retrospective descriptive study conducted at the Teaching and Research Institute of Hospital Israelita Albert Einstein, in which medical records and databases of patients with suspected neuroendocrine tumor of appendix and/or endometriosis of appendix were analyzed by imaging.

Results

Twenty-eight patients were included, all of which had some type of appendix alteration on the ultrasound examination. The pathological outcome of the appendix found 25 (89.3%) lesions compatible with endometriosis and three (10.7%) neuroendocrine tumors. The clinical findings of imaging and surgery were compared with the result of pathological anatomy by means of relative frequency.

Conclusion

It was possible to observe a higher prevalence of appendix endometriosis when the patient presented more intense pain symptoms. The image observed on ultrasound obtained a high positive predictive value for appendicular endometriosis.

Comparison between CT-enterography and MR-enterography for the diagnosis of right-sided deep infiltrating endometriosis of the bowel

OBJECTIVE

To compare computed tomography-enterography (CTE) and magnetic resonance-enterography (MRE) in the detection of right-sided bowel deep infiltrating endometriosis (DIE).

MATERIALS AND METHODS

Fifty women with DIE who underwent preoperatively CTE and MRE were included. CTE and MRE were first analyzed separately by two independent readers who analyzed five bowel segments (cecum, appendix, ileocecal junction, distal ileum and proximal small bowel [i.e., proximal ileum and jejunum]) for the presence of DIE and then interpreted in consensus. CTE, MRE and CTE with MRE were compared in terms of sensitivity, specificity and accuracy. Interobserver agreement was assessed with kappa (κ) test.

RESULTS

Using the reference standard 25 out 250 bowel segments were involved by DIE in 18 women and 225 were free of DIE. Sensitivity, specificity, and accuracy of CTE were 60% (95% confidence interval [CI]: 39-79), 93% (95% CI: 89-96) and 90% (95% CI: 85-93) for Reader 1, respectively, and 52% (95% CI: 31-72), 99% (95% CI: 97-100) and 94% (95% CI: 91-97) for Reader 2, with no differences in sensitivity (P = 0.564) and specificity (P = 0.181) between readers and fair interobserver agreement (κ = 0.37). For MRE these figures were 52% (95% CI: 31-72), 92% (95% CI: 88-95) and 88% (95% CI: 84-92) for Reader 1 and 60% (95% CI: 39-79), 99% (95% CI: 96-100) and 95% (95% CI: 91-97) for Reader 2, with no differences in sensitivity (P = 0.157) and specificity (P = 0.061) between readers and fair interobserver agreement (κ = 0.31). Significant differences in sensitivity (20%; 95% CI: 7-41) were found between CTE + MRE vs. CTE alone for Reader 1 and vs. MRE alone for Reader 2 (P = 0.041 for both) CONCLUSION: CTE and MRE have not different sensitivities and convey only fair interobserver agreement but are highly specific for the diagnosis of right-sided bowel DIE. CTE and MRE are complementary because they improve the detection of DIE implants when used in combination.

Endometriosis: A multimodal imaging review

Endometriosis is a chronic inflammatory disorder characterized endometrial-like tissue present outside of the uterus, affecting approximately 10% of reproductive age women. It is associated with abdomino-pelvic pain, infertility and other non - gynecologic symptoms, making it a challenging diagnosis. Several guidelines have been developed by different international societies to diagnose and classify endometriosis, yet areas of controversy and uncertainty remains. Transvaginal ultrasound (TV-US) is the first-line imaging modality used to identify endometriosis due to its accessibility and cost-efficacy. Enhanced sonographic techniques are emerging as a dedicated technique to evaluate deep infiltrating endometriosis (DIE), depending on the expertise of the sonographer as well as the location of the lesions. MRI is an ideal complementary modality to ultrasonography for pre-operative planning as it allows for a larger field-of-view when required and it has high levels of reproducibility and tolerability. Typically, endometriotic lesions appear hypoechoic on ultrasonography. On MRI, classical features include DIE T2 hypointensity, endometrioma T2 hypointensity and T1 hyperintensity, while superficial peritoneal endometriosis (SPE) is described as a small focus of T1 hyperintensity. Imaging has become a critical tool in the diagnosis, surveillance and surgical planning of endometriosis. This literature review is based mostly on studies from the last two decades and aims to provide a detailed overview of the imaging features of endometriosis as well as the advances and usefulness of different imaging modalities for this condition.

Conservative Management of Rectovaginal Deep Endometriosis: Shaving Should Be Considered as the Primary Surgical Approach in a High Majority of Cases

Deep endometriosis infiltrating the rectum remains a challenging situation to manage, and it is even more important when ureters and pelvic nerves are also infiltrated. Removal of deep rectovaginal endometriosis is mandatory in case of symptoms strongly impairing quality of life, alteration of digestive, urinary, sexual and reproductive functions, or in case of growing. Extensive preoperative imaging is required to choose the right technique between laparoscopic shaving, disc excision, or rectal resection. When performed by skilled surgeons and well-trained teams, a very high majority of cases of deep endometriosis nodule (>95%) is feasible by the shaving technique, and this is associated with lower complication rates regarding rectal resection. In most cases, removing a part of the rectum is questionable according to the risk of complications, and the rectum should be preserved as far as possible. Shaving and rectal resection are comparable in terms of recurrence rates. As shaving is manageable whatever the size of the lesions, surgeons should consider rectal shaving as first-line surgery to remove rectal deep endometriosis. Rectal stenosis of more than 80% of the lumen, multiple bowel deep endometriosis nodules, and stenotic sigmoid colon lesions should be considered as indication for rectal resection, but this represents a minority of cases.

The "Speckle Sign" in the Diagnosis of Posterior Compartment Endometriosis

OBJECTIVE

To determine usefulness of the "speckle sign" in the diagnosis of deep invasive endometriosis.

MATERIALS AND METHODS

This HIPAA-compliant, institutional review board-approved retrospective study with informed consent waived included 25 women (mean age 20-69 years) with histopathologically confirmed posterior cul-de-sac endometriosis between 2013 and 2018. Transvaginal ultrasound exams of these patients were reviewed by 2 expert radiologists searching for the "speckle sign," defined as irregular obliteration of the posterior cul-de-sac and bright (hyperechoic) internal echoes. The frequency of additional findings such as "kissing ovaries," endometriomas in the adnexa, bowel tethering in the posterior pelvic compartment, retroflexed uterus, adenomyosis, and pelvic free fluid were also analyzed. Data regarding clinical features, histopathologic findings and management were collected through a review of the medical record.

RESULTS

Reader one identified posterior compartment endometriosis in 20/25 patients, and reader two in 22/25 patients, with 96% agreement. Adnexal endometriomas were found in 21/25 patients for both readers (k = 0.70) and were bilateral in 23% of patients. The ovaries were adherent to each other in the midline ("kissing ovaries") in 50% of patients; the bowel was tethered anteriorly in 20%; the presence of adenomyosis was seen in about 27%, and a retroflexed uterus was seen in 24% of patients.

CONCLUSIONS

The speckle sign could be helpful in making the diagnosis of posterior compartment endometriosis, and the sign is often found in conjunction with other imaging features of endometriosis.

Two Cases of Endometriosis in the Cecum Detected by Contrast-enhanced Computed Tomography with Air/Carbon Dioxide Insufflation

We herein report two patients with endometriosis in the cecum. Both patients presented with a protruding, subepithelial tumor on colonoscopy and were diagnosed with cecal endometriosis after surgical resection. It is notable that the cecal lesions were not initially identified on computed tomography (CT), while CT colonography with air/carbon dioxide insufflation resulted in the detection of the cecal tumor. These cases highlight the possibility of false-negative results on conventional CT in patients with cecal endometriosis. We consider CT colonography with air/carbon dioxide insufflation useful for detecting cecal tumors in such cases.

Acute Appendicitis Secondary to Appendiceal Endometriosis

Endometriosis in the vermiform appendix is a rare condition that affects women of childbearing age. The clinical picture can simulate inflammatory acute abdominal pain, especially acute appendicitis. Laboratory and imaging tests may assist in the diagnosis but are not conclusive. This article reports a case of acute appendicitis caused by appendiceal endometriosis for which laparoscopic appendectomy and diagnostic confirmation were performed after histopathological analysis.

Deep endometriosis: The place of laparoscopic shaving

Deep endometriosis (DE) is considered to be one of the most challenging conditions to manage, especially when it invades surrounding organs like the rectum. Surgical excision of deep rectovaginal endometriosis is required when lesions are symptomatic, impairing bowel, urinary, sexual, and reproductive functions, or if they evolve. Preoperative radiological examination should be extensive to determine the appropriate surgery: laparoscopic shaving, disc excision, or rectal resection. We demonstrated that in the hands of experienced surgeons, rectal shaving is possible for DE in more than 95% of cases, with low complication rates compared to rectal resection. Shaving and bowel resection are associated with comparable recurrence rates. As shaving is indicated whatever the size of deep lesions, surgeons should first consider rectal shaving to remove DE. Bowel resection should only be performed in case of major rectal stenosis (>80%), multiple and/or posterior rectal lesions and stenotic sigmoid colon lesions.