Multimodality imaging and clinicopathologic assessment of abdominal wall endometriosis: knocking down the enigma

A rare case of extrapelvic endometriosis in the right sciatic notch

Endometriosis is described as the proliferation of endometrial tissue outside of the uterus. This most frequently occurs within the pelvis and is a common cause of chronic pelvic pain in women of reproductive age. Rarely, endometriosis can manifest outside of the pelvis and can uncommonly involve the musculoskeletal and peripheral nervous systems. Extrapelvic endometriosis is a difficult radiologic diagnosis due to its rarity and varied magnetic resonance imaging (MRI) appearance. Diagnosis of extrapelvic endometriosis is most frequently made with biopsy and most cases within the literature are treated with surgical resection. Of the cases that were treated medically, there is a paucity of available follow-up imaging to characterize the natural history and treatment response of this entity. We present a case of extrapelvic endometriosis involving the right sciatic notch, in a 26 year old female who presented with cyclic hip pain and lumbosacral plexopathy. Initial MRI findings were nonspecific, and diagnosis was made via image guided biopsy. The patient underwent medical treatment with a gonadotropin-release hormone agonist and oral contraceptives, with close imaging follow-up including a 6-month post-treatment MRI.

Rectus Abdominis Muscle Endometriosis: A Unique Case Report with a Literature Review

Introduction and importance: Extrapelvic endometriosis, confined exclusively to the body of the rectus abdominis muscle, is a rare form of abdominal wall endometriosis. While its etiopathology remains unclear, it is often diagnosed in healthy women who present with atypical symptoms and localization unrelated to any incision site, or in the absence of a history of endometriosis or previous surgery. Presentation of the case: Here, we describe a unique case of intramuscular endometriosis of the rectus abdominis muscle in a healthy 39-year-old Caucasian woman. The condition was located away from any prior incisional scars and presented without typical symptoms or concurrent pelvic disease, making diagnostic imaging unclear. After partial surgical resection of the endometriotic foci, the diagnosis was confirmed histologically. Progestogen-based supportive medication was initiated to prevent the need for additional surgeries and to reduce the risk of recurrence. After 6 years of follow-up and continued progestogen treatment, the patient remains symptom-free and has shown no recurrence of the disease. Clinical discussion: Endometriosis of the rectus abdominis muscle exhibits specific characteristics in terms of localization, etiopathology, symptomatology, and diagnostic imaging, suggesting that it should be considered a distinct clinical entity. Conclusions: Although rare, primary endometriosis of the rectus abdominis muscle should be included in the differential diagnosis for women of childbearing age. Early diagnosis is essential to avoid delayed recognition, tissue damage, and to minimize the risk of recurrence or malignant transformation. Given the increasing frequency of gynecologic and laparoscopic surgeries worldwide, it is crucial to establish standardized reporting protocols, follow-up timelines, and imaging assessments during specific phases of the menstrual cycle. Standardization will help raise awareness of this disease, and further our understanding of its pathogenesis, risk factors, recurrence patterns, and potential for malignant transformation-factors that are still not fully understood.

CAR/CSAR Practice Statement on Pelvic MRI for Endometriosis

The Canadian Association of Radiologists (CAR) Endometriosis Working Group was tasked with providing guidance and benchmarks to ensure the quality of technique and interpretation for advanced imaging modalities associated with diagnosing endometriosis. Advanced pelvic ultrasound is essential in diagnosing and mapping pelvic endometriosis, but pelvic MRI serves as an excellent imaging tool in instances where access to advanced ultrasound is limited, or an alternative imaging modality is required. Despite the known utility of MRI for endometriosis, there is no consensus on imaging protocol and patient preparation in Canada. To improve patient care and support excellence in imaging, the Working Group has developed recommendations for the use of pelvic MRI to assess for endometriosis with an aim to standardize MRI technique for use in both community and academic practices across Canada. The guidelines provide recommendations regarding imaging technique and patient preparation for pelvic MRI, along with suggestions for structured reporting of pelvic MRI for endometriosis.

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.

Abdominal wall endometrioma after Cesarean section: a case series

Abdominal wall endometrioma (AWE) results from endometrial-like tissue implants in the abdominal wall after uterine surgery. While the diagnosis can be challenging, an abdominal mass at the site of a previous incision accompanied by cyclical pain and enlargement correlating with menstruation is highly suspicious. Excision is indicated for symptomatic relief as well as the probability of malignant transformation. Because signs and symptoms are similar to other soft tissue lesions, general surgeons are sought out for excision and thus encounter the majority of AWE cases. Here, we present two patients of similar age who both presented to our hospital within one month, each found to have an endometrioma at the site of a Pfannenstiel scar after Cesarean section, and were managed operatively.

Imaging Features of Soft Tissue Tumor Mimickers: A Pictorial Essay

Soft tissue lesions are commonly encountered and imaging is an important diagnostic step in the diagnosis and management of these lesions. While some of these lesions are true neoplasms, others are not. These soft tissue tumor mimickers can be due to a variety of conditions including traumatic, iatrogenic, inflammatory/reactive, infection, vascular, and variant anatomy. It is important for the radiologist and clinician to be aware of these common soft tissue tumor mimickers and their characteristic imaging features to avoid unnecessary workup and provide the best treatment outcome.

Pelvic MRI in the diagnosis and staging of pelvic endometriosis: added value of structured reporting and expertise

PURPOSE

To compare the diagnostic characteristics of routine-read (RR), structured-reported read (SR), and structured expert-read pelvic (SER) MRI for staging of pelvic endometriosis in a tertiary care academic center.

METHODS

Of 530 patients with endometriosis (2013-2018), 59/530 (11.1%) were staged surgically and underwent pelvic MRI. Radiology reports were considered RR; MRI studies were independently reassessed by SR and SER. Involvement was recorded by compartment [anterior (AC), middle (MC), posterior (PC), adnexal (AX), and other (OC)]. Diagnostic discrepancy between review methods was assessed with McNemar's test. Interobserver agreement was assessed using Cohen's unweighted kappa.

RESULTS

Of 295 compartments in 59 women (mean age = 38.8 years; range 20-69), 147/295 (49.8%) had confirmed endometriosis. Overall sensitivity: RR = 42.9%; SR = 86.4%; SER = 74.2%. SR's increased sensitivity was significant for PC (p < 0.001), MC (p < 0.001), AC (p = 0.001), AX (p = 0.038). Higher sensitivity by SER was significant for PC (p < 0.001), MC (p = 0.004) and AC (p < 0.001), but not AX (p > 0.05). Overall specificity: RR = 95.3%; SR = 45.9%; SER = 81.8%. SER specificity was no different than RR for PC or AX (p > 0.5). RR sensitivity relied heavily on detection of AX involvement, whereas SR and SER showed additional sites of disease while maintaining comparable specificity for SER. Overall agreement between SR and SER was fair [k = 0.342 (95% CI 0.25, 0.44)].

CONCLUSIONS

Even at a tertiary care academic center, SER outperforms both SR and RR in the assessment of pelvic endometriosis. Although lack of expertise may negatively impact specificity, use of structured reporting is significantly more sensitive than RR. Therefore, its use can be of assistance in surgical planning and patient counseling.

Encyclopedia of endometriosis: a pictorial rad-path review

Endometriosis affects approximately 10% of reproductive age women and represents a significant cause of pelvic pain and infertility. Unfortunately, the diagnosis of endometriosis is often delayed by years. Endometriosis may manifest as cystic lesions in the ovaries known as endometriomas. Superficial endometriosis is typically detected by laparoscopy along the pelvic peritoneum as these lesions tend to be difficult to detect by imaging. Deep infiltrative endometriosis may be detected by ultrasound, CT or MRI in classic locations within the pelvis, such as the posterior cul-de-sac and uterosacral ligaments. Endometriosis may also involve the thorax, gastrointestinal and urinary tracts, and locations such as the abdominal wall and abdominal organs. We present MRI and CT case examples, together with corresponding laparoscopic and histopathology images to enhance radiologists' understanding of this disease.

Abdominal wall endometriosis (a narrative review)

One of the rarest forms of endometriosis is abdominal wall endometriosis (AWE), which includes caesarean scar endometriosis. AWE remains a challenging condition because some issues related to this topic are still under debate. The increasing number of caesarean sections and laparotomies will expect to increase the rate of AWE. The current incidence in obstetrical and gynaecological procedures is still unknown. The disease is probably underestimated. The pathogenic mechanism involves local environment at the implant site including local inflammation and metalloproteinases activation due to local growth factors, estrogen stimulation through estrogen receptors and potential epigenetic changes. However, the underlying mechanisms are not fully explained, and we need more experimental models to understand them. The clinical presentation is heterogeneous; the patient may be seen by a gynaecologist, an endocrinologist, a general surgeon, an imaging specialist, or even an oncologist. No particular constellation of clinical risk factors has been identified, and the histological report is the major diagnostic tool for confirmation. Surgery is the first line of therapy. Further on we need protocols for multidisciplinary investigations and approaches.