Canadian Association of Radiologists Practice Guidelines for Computed Tomography Colonography.

Colon cancer is the third most common malignancy in Canada. Computed tomography colonography (CTC) provides a creditable and validated option for colon screening and assessment of known pathology in patients for whom conventional colonoscopy is contraindicated or where patients self-select to use imaging as their primary modality for initial colonic assessment. This updated guideline aims to provide a toolkit for both experienced imagers (and technologists) and for those considering launching this examination in their practice. There is guidance for reporting, optimal exam preparation, tips for problem solving to attain high quality examinations in challenging scenarios as well as suggestions for ongoing maintenance of competence. We also provide insight into the role of artificial intelligence and the utility of CTC in tumour staging of colorectal cancer. The appendices provide more detailed guidance into bowel preparation and reporting templates as well as useful information on polyp stratification and management strategies. Reading this guideline should equip the reader with the knowledge base to perform colonography but also provide an unbiased overview of its role in colon screening compared with other screening options.

Case Report: Identification of a novel STAT3 mutation in EBV-positive inflammatory follicular dendritic cell sarcoma.

EBV-positive inflammatory follicular dendritic cell sarcoma (EBV+ IFDCS) is an uncommon disease primarily observed in Asia. It is characterized by the development of tumors believed to originate from follicular dendritic cells (FDC). The consistent association between this condition and clonal EBV infection suggests EBV's involvement as an etiological factor. However, diagnosing EBV+ IFDCS can be challenging due to its morphological variability and diverse immunohistochemical staining patterns. The genetic characteristics of EBV+ IFDCS remain insufficiently understood. To address this knowledge gap, we present a case study of a 47-year-old male patient diagnosed with EBV+ IFDCS. We utilized a Next-generation sequencing (NGS) platform to investigate the genetic profile of the tumor cells. We identified a single pathogenic mutation (G618R) in the STAT3 gene. This finding provides valuable insights into the genetic alterations associated with EBV+ IFDCS and potentially contributes to our understanding of the disease's pathogenesis.

Effects of ionizing radiation exposure during pregnancy.

PURPOSE: To review the effects of ionizing radiation to the conceptus and the relationship to the timing of the exposure during pregnancy. To consider strategies that would mitigate potential harms associated with exposure to ionizing radiation during pregnancy. METHODS: Data reported in the peer-reviewed literature on entrance KERMA received from specific radiological examinations were combined with published results from experiment or Monte Carlo modeling of tissue and organ doses per entrance KERMA to estimate total doses that could be received from specific procedures. Data reported in the peer-reviewed literature on dose mitigation strategies, best practices for shielding, consent, counseling and emerging technologies were reviewed. RESULTS: For procedures utilizing ionizing radiation for which the conceptus is not included in the primary radiation beam, typical doses are well below the threshold for causing tissue reactions and the risk of induction of childhood cancer is low. For procedures that include the conceptus in the primary radiation field, longer fluoroscopic interventional procedures or multiphase/multiple exposures potentially could approach or exceed thresholds for tissue reactions and the risk of cancer induction must be weighed against the expected risk/benefit of performing (or not) the imaging examination. Gonadal shielding is no longer considered best practice. Emerging technologies such as whole-body DWI/MRI, dual-energy CT and ultralow dose studies are gaining importance for overall dose reduction strategies. CONCLUSION: The ALARA principle, considering potential benefits and risks should be followed with respect to the use of ionizing radiation. Nevertheless, as Wieseler et al. (2010) state, "no examination should be withheld when an important clinical diagnosis is under consideration." Best practices require updates on current available technologies and guidelines.

Gestational trophoblastic disease: an update.

Gestational trophoblastic diseases (GTD) encompass a spectrum of rare pre-malignant and malignant entities originating from trophoblastic tissue. This updated review will highlight important radiological features, pathology and classification, and provide insight into the clinical management of these uncommon disorders. There is a wide geographic variation with the incidence of hydatidiform mole varying between 0.57 and 2 per 1000 pregnancies. The use of ultrasound (US) in the management of early pregnancy symptoms and complications has positively impacted the earlier detection of these diseases and resulted in diminished morbidity. Additional imaging modalities are reserved for problem solving or assessment of pulmonary manifestations of molar pregnancy. Having an awareness of their pleomorphic sonographic presentation and additional pathology that can mimic GTD is critical to avoiding pitfalls. Histologic and molecular analysis further aids in differential diagnosis. Gestational trophoblastic neoplasia (GTN) is inclusive of all malignant GTDs, and arises after 20% of molar pregnancies but can also be seen with non-molar gestations. Biochemical monitoring with human chorionic gonadotrophin is imperative for ongoing monitoring and surveillance and allows early detection of this entity. Doppler US is used for confirmation of diagnosis with magnetic resonance imaging (MRI) reserved for problem solving or assessment of myometrial invasion. This is of heightened relevance in patients undergoing surgical management. Cross sectional imaging is reserved for patients in the setting of GTN for the purposes of staging, prognostication and in the setting of recurrent disease. This may require a combination of computed tomography, MRI and positron emission tomography. Doppler US can provide insight into chemotherapeutic response/predict resistance in patients with GTN. As our understanding of these disorders evolves, there has been maturation in management options with a shift from traditional chemotherapy to innovative immunotherapy, particularly in the setting of resistant or high-risk disease.

Management of Malignant Bowel Obstruction: An Innovative Proactive Outpatient Nurse-Led Model of Care for Patients With Advanced Gynecologic Cancer.

BACKGROUND: Malignant bowel obstruction (MBO) in patients with advanced gynecologic cancer (GyCa) can negatively impact clinical outcomes and quality of life. Oncology nurses can support these patients with adequate tools/processes. PROBLEM: Patients with GyCa with/at risk of MBO endure frequent emergency or hospital admissions, impacting patient care. APPROACH: Optimizing oncology nurses' role to improve care for patients with GyCa with/at risk of MBO, the gynecology oncology interprofessional team collaborated to develop a proactive outpatient nurse-led MBO model of care (MOC). OUTCOMES: The MBO MOC involves a risk-based algorithm engaging interdisciplinary care, utilizing standardized tools, risk-based assessment, management, and education for patients and nurses. The MOC has improved patient-reported confidence level of bowel self-management and decreased hospitalization. Following education, nurses demonstrated increased knowledge in MBO management. CONCLUSIONS: An outpatient nurse-led MBO MOC can improve patient care and may be extended to other cancer centers, fostering collaboration and best practice.

18F-DCFPyL PET/CT in advanced high-grade epithelial ovarian cancer: A prospective pilot study.

Objectives: Glutamate carboxypeptidase-II (GCP-II), a zinc metalloenzyme that resides in cell membrane, has been reported as overexpressed in the neovasculature of ovarian cancers. The study objective was to determine whether GCP-II targeted imaging with 18F-DCFPyL PET/CT can detect disease sites in women with advanced high-grade serous ovarian cancer (HGSOC). Materials and methods: Twenty treatment-naïve women with advanced HGSOC were recruited (median age 60 years). Prior to commencing therapy (primary cytoreductive surgery [n=9] or neoadjuvant chemotherapy [n=11]), subjects underwent routine staging with contrast-enhanced abdominopelvic CT (=CT), followed by 18F-DCFPyL PET/CT (=PET). CT and PET were reported independently using a standardized reporting template assessing 25 sites. The performance of PET was compared to CT in all subjects and to surgery and surgical histopathology in 9 patients who underwent primary cytoreductive surgery. Results: Of the 25 sites assessed in 20 patients, CT detected disease in 292/500 (58.4%) locations and PET detected disease in 171/500 (34.2%). Compared to CT the sensitivity (95% CI) of PET to detect disease in the upper abdomen, the gastrointestinal tract or the peritoneum was 0.29 (0.20,0.40), 0.21 (0.11,0.33) and 0.74 (0.64,0.82), respectively. In the surgical cohort, 220 sites in 9 patients were evaluated. The sensitivity and specificity of CT and PET were 0.85 versus 0.54 (p<0.001) and 0.73 versus 0.93 (p<0.001), respectively. Conclusion: Although 18F-DCFPyL has higher specificity than CT in detecting advanced HGSOC tumor sites, it detects less disease sites than CT, especially in the upper abdomen and along the gastrointestinal tract, likely limiting its clinical utility. Clinical trial registration: ClinicalTrials.gov, NCT03811899.

External Validation of O-RADS US Risk Stratification and Management System.

Background The Ovarian-Adnexal Reporting and Data System (O-RADS) US risk stratification and management system (O-RADS US) was designed to improve risk assessment and management of ovarian and adnexal lesions. Validation studies including both surgical and nonsurgical treatment as the reference standard remain lacking. Purpose To externally validate O-RADS US in women who underwent either surgical or nonsurgical treatment and to determine if incorporating acoustic shadowing as a benign finding improves diagnostic performance. Materials and Methods This retrospective study included consecutive women who underwent pelvic US between August 2015 and April 2017 at a tertiary referral oncology center. Two independent readers blinded to clinical and histologic outcome assigned an O-RADS risk category and an International Ovarian Tumor Analysis (IOTA) Assessment of Different NEoplasias in the adneXa (ADNEX) model risk of malignancy score to assessable lesions. Reference standards were surgical histopathology or 2-year imaging follow-up. Receiver operating characteristic (ROC) curve analysis was used to evaluate performance of the O-RADS US, ADNEX, and modified O-RADS models incorporating acoustic shadowing. Results In total, 227 women (mean age, 52 years ± 16 [SD]) with 262 ovarian or adnexal lesions were evaluated. Of these lesions, 187 (71%) were benign and 75 (29%) were malignant. The proportion of malignancy was 0% (0 of 100) for O-RADS 2, 3% (one of 32) for O-RADS 3, 35% (22 of 63) for O-RADS 4, and 78% (52 of 67) for O-RADS 5. The area under the ROC curve (AUC) for O-RADS and ADNEX was 0.91 (95% CI: 0.88, 0.94) and 0.95 (95% CI: 0.92, 0.97; P = .01), respectively. The addition of acoustic shadowing as a benign finding improved O-RADS AUC to 0.94 (95% CI: 0.91, 0.96; P = .01). Use of O-RADS 4 as a threshold yielded a sensitivity of 99% (74 of 75; 95% CI: 96, 100) and a specificity of 70% (131 of 187; 95% CI: 64, 77). Conclusion In a tertiary referral oncology center, the Ovarian-Adnexal Reporting and Data System US risk stratification and management system enabled accurate distinction of benign from malignant ovarian and adnexal lesions. Adding acoustic shadowing as a benign finding improved its diagnostic performance. © RSNA, 2022 See also the editorial by Levine in this issue.

Interobserver and intraobserver variability of RECIST assessment in ovarian cancer.

OBJECTIVES: Measurement of Response Evaluation Criteria In Solid Tumors (RECIST) relies on reproducible unidimensional tumor measurements. This study assessed intraobserver and interobserver variability of target lesion selection and measurement, according to RECIST version 1.1 in patients with ovarian cancer. METHODS: Eight international radiologists independently viewed 47 images demonstrating malignant lesions in patients with ovarian cancer and selected and measured lesions according to RECIST V.1.1 criteria. Thirteen images were viewed twice. Interobserver variability of selection and measurement were calculated for all images. Intraobserver variability of selection and measurement were calculated for images viewed twice. Lesions were classified according to their anatomical site as pulmonary, hepatic, pelvic mass, peritoneal, lymph nodal, or other. Lesion selection variability was assessed by calculating the reproducibility rate. Lesion measurement variability was assessed with the intra-class correlation coefficient. RESULTS: From 47 images, 82 distinct lesions were identified. For lesion selection, the interobserver and intraobserver reproducibility rates were high, at 0.91 and 0.93, respectively. Interobserver selection reproducibility was highest (reproducibility rate 1) for pelvic mass and other lesions. Intraobserver selection reproducibility was highest (reproducibility rate 1) for pelvic mass, hepatic, nodal, and other lesions. Selection reproducibility was lowest for peritoneal lesions (interobserver reproducibility rate 0.76 and intraobserver reproducibility rate 0.69). For lesion measurement, the overall interobserver and intraobserver intraclass correlation coefficients showed very good concordance of 0.84 and 0.94, respectively. Interobserver intraclass correlation coefficient showed very good concordance for hepatic, pulmonary, peritoneal, and other lesions, and ranged from 0.84 to 0.97, but only moderate concordance for lymph node lesions (0.58). Intraobserver intraclass correlation coefficient showed very good concordance for all lesions, ranging from 0.82 to 0.99. In total, 85% of total measurement variability resulted from interobserver measurement difference. CONCLUSIONS: Our study showed that while selection and measurement concordance were high, there was significant interobserver and intraobserver variability. Most resulted from interobserver variability. Compared with other lesions, peritoneal lesions had the lowest selection reproducibility, and lymph node lesions had the lowest measurement concordance. These factors need consideration to improve response assessment, especially as progression free survival remains the most common endpoint in phase III trials.

A Multi-Disciplinary Approach to Perianal Fistulizing Crohn's Disease.

Perianal fistulizing Crohn's disease represents a severe phenotype associated with significant morbidity. Patients with perianal fistulizing disease are more likely to have a severe disease course and have significant reductions in quality of life. Moreover, these patients are at risk for the development of distal rectal and anal cancers. Given the complexity and severity of this patient group, the management of perianal Crohn's disease must be undertaken by a multidisciplinary team. The gastroenterologist and colorectal surgeon play a critical role in the diagnosis and management of perianal fistulizing disease. An examination under anesthesia provides critical information and is an essential part of the work-up of complex perianal fistulas. The radiologist also plays a central role in characterizing anatomy and assessing response to treatment. Several imaging modalities are available for these patients with magnetic resonance imaging as the imaging modality of choice. Perianal disease developing after ileal pouch-anal anastomosis represents a particularly challenging form of fistulizing disease and requires a multidisciplinary clinical and radiologic approach to differentiate surgical complications from recurrent Crohn's disease.

O-RADS for Ultrasound: A User's Guide, From the AJR Special Series on Radiology Reporting and Data Systems.

The Ovarian-Adnexal Reporting and Data System (O-RADS) is a lexicon and risk stratification tool designed for the accurate characterization of adnexal lesions and is essential for optimal patient management. O-RADS is a recent addition to the American College of Radiology (ACR) reporting and data systems and consists of ultrasound (US) and MRI arms. Since most ovarian or adnexal lesions are first detected with US, O-RADS US is considered the primary assessment tool. Application of O-RADS US is recommended whenever a nonphysiologic lesion is encountered. Lesion characterization may be streamlined by use of an algorithmic approach focused on relevant features and an abbreviated version of the lexicon. Resources to expedite O-RADS US categorization and determination of a management recommendation include easy online access to the ACR color-coded risk stratification scorecards and an O-RADS US calculator that is available as a smartphone app. Reporting should be concise and include relevant features for risk stratification that adhere to lexicon terminology. Technical considerations include optimization of gray-scale and color Doppler technique and performance of problem-solving maneuvers to help avoid common pitfalls. This review provides a user-friendly summary of O-RADS US with practical tips for everyday clinical use.

Utilization of Diagnostic Imaging and Ionization Radiation Exposure Among an Inflammatory Bowel Disease Inception Cohort.

BACKGROUND: Abdominal imaging is important in managing inflammatory bowel disease (IBD). We characterized utilization of imaging and exposure to ionizing radiation. METHODS: We enumerated abdominal diagnostic imaging in a population-based cohort of IBD patients between 1994 and 2016. Trends in utilization of abdominal computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound were characterized. Cumulative doses of ionizing radiation were compared between IBD patients and non-IBD controls and between Crohn's disease (CD) and ulcerative colitis (UC) patients. Regression models were constructed to assess predictors of high ionizing radiation exposure. RESULTS: There were 72,933 incident cases of IBD. During the first 5 years of diagnosis, IBD patients were exposed to nearly 6-fold higher exposure to cumulative ionizing radiation attributable to abdominal imaging compared with non-IBD controls (18.6 mSv vs 2.9 mSv). Cumulative ionizing radiation exposure was higher in CD than UC (26.0 mSv vs 12.0 mSv; P < 0.001). Crohn's disease patients were more than twice as likely as UC patients to exceed 50 mSv (15.6% vs 6.2%; P < 0.001) and 100 mSV (5.0% vs 2.1%; P < 0.001). There was geographic variation in ionizing radiation exposure, and individuals of lower income were more likely to have high exposure. Utilization of abdominal MRI has increased substantially, peaking between 2007 and 2012 and increasing annually at 34%, which coincided with an annual 2% decline in the use of abdominal CT. CONCLUSIONS: Crohn's disease patients are at highest risk for high exposure to ionizing radiation, with a subgroup receiving potentially harmful levels. Increasing utilization and access to abdominal MRI may alleviate exposure.

Imaging and implications of tumor thrombus in abdominal malignancies: reviewing the basics.

Extension of tumor tissue within a vein is a recognized prognostic factor in abdominal malignancy because of its influence on tumor staging and selection of therapeutic management. With the advent of newer surgical techniques, and variable treatment strategies, imaging plays a crucial role in categorizing patients according to the tumor resectability and vascular reconstruction techniques during surgery. Understanding the clinical impact of tumor thrombus increases the awareness of the radiologist about the key findings in tumor staging and decision-making of surgical approach. Ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) can be used individually and in combination to accurately assess the tumor thrombus. In our pictorial review, we will discuss the imaging findings and clinical consequences of tumor thrombosis in abdominal malignancies, including hepatocellular carcinoma, pancreatic neuroendocrine tumor, renal cancer, and adrenal cortical carcinoma.

Optimizing the Care of Malignant Bowel Obstruction in Patients With Advanced Gynecologic Cancer.

PURPOSE: Malignant bowel obstruction (MBO) is a common and distressing complication in women with advanced gynecologic cancer. A pilot, interprofessional MBO program was launched in 2016 at a large Canadian tertiary cancer center to integrate these patients' complex care needs across multiple disciplines and support women with MBO. METHOD: Retrospective analysis to evaluate the outcomes of women with advanced gynecologic cancer who were admitted to hospital because of MBO, before (2014 to 2016: baseline group) and after (2016 to 2018) implementation of the MBO program. RESULTS: Of the 169 women evaluated, 106 and 63 were in the baseline group and MBO program group, respectively. Most had ovarian cancer (n = 124; 73%) and had small-bowel obstruction (n = 131; 78%). There was a significantly shorter cumulative hospital length of stay (LOSsum) within the first 60 days of MBO diagnosis in the MBO program group compared with the baseline group (13 v 22 days, respectively; adjusted P = .006). The median overall survival for women treated in the MBO program was also significantly longer compared with the baseline group (243 v 99 days, respectively; adjusted P = .002). Using the interprofessional MBO care platform, a greater proportion of patients received palliative chemotherapy (83% v 56%) and less surgery (11% v 21%) in the MBO program group than in the baseline group, respectively. A subgroup of women (n = 11) received total parenteral nutrition for longer than 6 months. CONCLUSION: Implementation of a comprehensive, interprofessional MBO program significantly affects patient care and may improve outcomes. Unique to this MBO program is an integrated outpatient model of care and education that empowers patients to recognize MBO symptoms for early intervention.

Malignant Bowel Obstruction in Advanced Gynecologic Cancers: An Updated Review from a Multidisciplinary Perspective.

Malignant bowel obstruction (MBO) is a major complication in women with advanced gynecologic cancers which imposes a significant burden on patients, caregivers, and healthcare systems. Symptoms of MBO are challenging to palliate and result in progressive decompensation of already vulnerable patients with limited therapeutic options and a short prognosis. However, there is a paucity of guidelines or innovative approaches to improve the care of women who develop MBO. MBO is a complex clinical situation that requires a multidisciplinary approach to ensure the appropriate treatment modality and interprofessional care to optimally manage these patients. This review summarizes the current literature on the different approaches targeting MBO management including surgical intervention, chemotherapy, total parenteral nutrition, and pharmacological treatment. In addition, the impact of MBO management on patients' quality of life (QOL) is examined. This article focuses on the challenges in developing evidence-based treatment guidelines for MBO and barriers in clinical trial design for MBO and proposes strategies to advance the MBO management. Collaboration is essential to design studies that may improve the overall care and quality of life for these patients. Prospective data are needed to inform clinical practice, establish a new benchmark for evidence-based MBO management, and better understand the biology of MBO.

Resisting RECIST-Uniformity Versus Clinical Validity.

OBJECTIVES: The Response Evaluation Criteria in Solid Tumors (RECIST) International Working Group developed criteria for tumor response and progression to standardize radiological assessment in patients receiving chemotherapy in phase 2 trials. However, it is unclear whether the defined percentage change in tumor size and volume reflects true clinical benefit for the patient. The RECIST criteria were designed to improve objectivity in trials, but not to replace clinical decision making. The aim of this study was to understand clinicians' opinions about RECIST in current oncology practice. METHODS: Using Web-based questionnaires, we investigated attitudes to the use of RECIST at a large comprehensive cancer center and in an international group of gynecologic cancer specialists through the Gynecologic Cancer InterGroup. The results reported here relate to the survey focusing on gynecologic cancer. RESULTS: Sixty medical professionals from 13 countries responded to the survey. The majority of respondents worked at a tertiary or specialist cancer center (51; 86%). Overall, 66% of respondents felt RECIST increased trial objectivity and was a good measure of response. The majority of respondents (81%) reported that they infrequently challenged RECIST evaluation. Overall, 60% felt more than 10% of patients came off trial for clinical rather than radiological progression. In the context of a new small lesion, only 35% felt that should always be considered disease progression. The importance of both clinician and radiologist input was highlighted with nontarget progression. Nontarget progression and target progression were recognized as equally important for clinical decision making (72%). CONCLUSIONS: RECIST is a key criterion for endpoint assessment in clinical trials with its value recognized by clinicians. However, this survey also highlights the practical limitations of RECIST. Disconnect can be seen between the radiological result and the clinical picture-learning from these patients is critical. Continued efforts to improve metrics assessing patient benefit in trials remains a priority.

Modified Delphi Process for the Development of Choosing Wisely for Inflammatory Bowel Disease.

BACKGROUND AND AIMS: The prevalence and incidence of inflammatory bowel disease (IBD) in North America is among the highest in the world and imparts substantial direct and indirect medical costs. The Choosing Wisely Campaign was launched in wide variety of medical specialties and disciplines to reduce unnecessary or harmful tests or treatment interventions. METHODS: The Choosing Wisely list for IBD was developed by the Canadian IBD Network for Research and Growth in Quality Improvement (CINERGI) in collaboration with Crohn's and Colitis Canada (CCC) and the Canadian Association of Gastroenterology (CAG). Using a modified Delphi process, 5 recommendations were selected from an initial list of 30 statements at a face-to-face consensus meeting. RESULTS: The 5 things physicians and patients should question: (1) Don't use steroids (e.g., prednisone) for maintenance therapy in IBD; (2) Don't use opioids long-term to manage abdominal pain in inflammatory bowel disease (IBD); (3) Don't unnecessarily prolong the course of intravenous corticosteroids in patients with acute severe ulcerative colitis (UC) in the absence of clinical response; (4) Don't initiate or escalate long-term medical therapies for the treatment of IBD based only on symptoms; and (5) Don't use abdominal computed tomography (CT) scan to assess IBD in the acute setting unless there is suspicion of a complication (obstruction, perforation, abscess) or a non-IBD etiology for abdominal symptoms. CONCLUSIONS: The Choosing Wisely recommendations will foster patient-physician discussions to optimize IBD therapy, reduce adverse effects from testing and treatment, and reduce medical expenditure.

Primary perivascular epithelioid cell tumors of the liver: CT/MRI findings and clinical outcomes.

OBJECTIVES: The purpose of our study was to describe the CT and MRI features of primary PEComas of the liver and to document the associated clinical outcomes. METHODS: Retrospective study included 20 patients with primary hepatic perivascular epithelioid cell tumors (PEComa) with pathology and clinical outcomes for correlation. RESULTS: Study group included 20 patients: 16 women, 4 men; mean age 53 (range 35-77) years. Initial pathology diagnoses were classic angiomyolipoma (AML) (n = 11), epithelioid AML (n = 7), and PEComa not otherwise specified (n = 2). Mean tumor size was 5.1 (range 1.3-15.0) cm. CT/MRI features included well-defined margins 20/20 (100%), arterial enhancement 18/19 (95%), subcapsular location 17/20 (85%), heterogeneous 16/20 (80%), dysmorphic vessels 14/20 (70%), fat 13/20 (65%), hemorrhage 4/20 (20%), cystic components 4/20 (20%), and calcification 1/20 (5%). At the time of discovery, 18 patients were asymptomatic and their tumors were incidentally detected on imaging, and 2 patients were symptomatic. Ultimately, 18 tumors were benign and 2 developed metastases. CONCLUSIONS: On CT/MRI, most primary hepatic PEComas were well-defined, arterial enhancing, subcapsular, heterogeneous masses that often had dysmorphic vessels and contained fat. Most tumors were benign but complications included local symptoms, bleeding, and malignant change.