Fidelity to Best Practices in EPA Implementation: Outcomes Supporting Use of the Core Components Framework From the University of Virginia Entrustable Professional Activity Program.

PROBLEM: The rapid expansion of entrustable professional activity (EPA) assessment programs has led to calls to ensure fidelity in implementation and integrity in meeting the goals of competency-based medical education. Initiated in July 2017, in advance of the articulated core components of EPA implementation, this article describes the structure and outcomes of the University of Virginia (UVA) EPA Program and provides support for the identified essential components. APPROACH: The UVA EPA Program includes workplace assessments by residents/fellows, attending faculty, and master assessors (MAs), experienced clinicians who assess students across disciplines and clinical settings. All assessors participate in formal professional development and provide verbal and written comments to support their supervision ratings. The Entrustment Committee, composed of 12 MAs, uses a shared mental model and aggregates all assessor data to make a high-stakes summative entrustment decision about students' readiness to assume the role of an acting intern. OUTCOMES: Since 2017, over 2,000 assessors have completed 56,969 EPA assessments for 1,479 students. Ninety-four percent of assessments have been done during the clerkship phase. Residents/fellows have completed a mean of 18 assessments, attending faculty a mean of 27, and MAs a mean of 882. Seventy-four percent of observed encounters involved patients with acute concerns with or without a co-morbid condition. Fifty percent of assessments occurred in inpatient and 32% in ambulatory settings. Eighty-seven percent of assessments contained narrative comments with more than 100 characters. NEXT STEPS: Planned next steps will include earlier identification of students who require individualized learning to promote the development of skills related to EPAs, expansion of the remediation program to enable more students to engage in a clinical performance mastery elective, and creation of targeted professional development for assessors to reinforce the tenets of the EPA program.

The liver twist: A case of accessory liver lobe torsion presenting after mild trauma.

An accessory liver lobe is a congenital anomaly of hepatic tissue most commonly due to embryonic heteroplasia. Rarely, accessory liver lobes can undergo torsion and present as an acute surgical emergency. Although common in certain animals, there are only a few reported cases of accessory lobe torsion in humans. We report a multi-modality radiographic diagnosis of an acute torsion and subsequent infarct of an accessory liver lobe following minor trauma in a 29-year old male patient.

ACR Appropriateness Criteria® Suspected Small-Bowel Obstruction.

Small-bowel obstruction is a common cause of abdominal pain and accounts for a significant proportion of hospital admissions. Radiologic imaging plays the key role in the diagnosis and management of small-bowel obstruction as neither patient presentation, the clinical examination, nor laboratory testing are sufficiently sensitive or specific enough to diagnose or guide management. This document focuses on the imaging evaluation of the two most commonly encountered clinical scenarios related to small-bowel obstruction: the acute presentation and the more indolent, low-grade, or intermittent presentation. This document hopes to clarify the appropriate utilization of the many imaging procedures that are available and commonly employed in these clinical settings. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Crohn Disease.

Three common clinical scenarios involving use of imaging in Crohn disease are covered. These include the initial evaluation of Crohn disease when the diagnosis has not been previously established, the evaluation for anticipated exacerbation of known disease, and the evaluation of disease activity during therapy monitoring. The appropriateness of a given imaging modality for each scenario is rated as one of three categories (usually appropriate, may be appropriate, usually not appropriate) to help guide evaluation. Pediatric presentation of Crohn disease and the appropriateness of imaging are not covered in this document. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Palpable Abdominal Mass-Suspected Neoplasm.

Palpable abdominal masses may arise from the abdominal cavity or the abdominal wall. The differential diagnosis is broad for each variant ranging from benign lipomas, inflammatory processes, to malignant tumors. The imaging approach to diagnosis varies by location. For intra-abdominal masses, contrast-enhanced CT and ultrasound examination have demonstrated accuracy. For abdominal wall masses, which may arise from muscle, subcutaneous tissue, or connective tissue, MRI, CT, and ultrasound all provide diagnostic value. This publication reviews the current evidence supporting the imaging approach to diagnosis of palpable abdominal masses for two variants: suspected intra-abdominal neoplasm and suspected abdominal wall masses. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Dysphagia.

This review summarizes the relevant literature for the initial imaging of patients with symptoms of dysphagia. For patients with oropharyngeal dysphagia who have an underlying attributable cause, a modified barium swallow is usually appropriate for initial imaging but for those who have unexplained dysphagia a fluoroscopic biphasic esophagram is usually appropriate. Fluoroscopic biphasic esophagram is usually appropriate for initial imaging in both immunocompetent and immunocompromised patients who have retrosternal dysphagia. For postoperative patients with dysphagia, fluoroscopic single-contrast esophagram and CT neck and chest with intravenous (IV) contrast are usually appropriate for oropharyngeal or retrosternal dysphagia occurring in the early postoperative period where water-soluble contrast is usually preferred rather than barium sulfate. In the later postoperative period (greater than 1 month), CT neck and chest with IV contrast and fluoroscopic single-contrast esophagram are usually appropriate. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Left Lower Quadrant Pain-Suspected Diverticulitis.

This review summarizes the relevant literature regarding imaging of suspected diverticulitis as an etiology for left lower quadrant pain, and imaging of complications of acute diverticulitis. The most common cause of left lower quadrant pain in adults is acute sigmoid or descending colonic diverticulitis. Appropriate imaging triage for patients with suspected diverticulitis should address the differential diagnostic possibilities and what information is necessary to make a definitive management decision. Patients with diverticulitis may require surgery or interventional radiology procedures because of associated complications, including abscesses, fistulas, obstruction, or perforation. As a result, there has been a trend toward greater use of imaging to confirm the diagnosis of diverticulitis, evaluate the extent of disease, and detect complications before deciding on appropriate treatment. Additionally, in the era of bundled payments and minimizing health care costs, patients with acute diverticulitis are being managed on an outpatient basis and rapid diagnostic imaging at the time of initial symptoms helps to streamline and triage patients to the appropriate treatment pathway. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Right Upper Quadrant Pain.

Although right upper quadrant pain is a very common clinical presentation, it can be nonspecific. However, acute cholecystitis is very often the diagnosis of exclusion. This review focuses on the recommended imaging evaluation in the most commonly encountered clinical scenarios presenting with right upper quadrant abdominal pain, including suspected biliary disease, suspected acute cholecystitis, and suspected acalculous cholecystitis. This document hopes to clarify the appropriate utilization of the many imaging procedures that are available and commonly employed in these clinical settings. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Acute Nonlocalized Abdominal Pain.

The range of pathology in adults that can produce abdominal pain is broad and necessitates an imaging approach to evaluate many different organ systems. Although localizing pain prompts directed imaging/management, clinical presentations may vary and result in nonlocalized symptoms. This review focuses on imaging the adult population with nonlocalized abdominal pain, including patients with fever, recent abdominal surgery, or neutropenia. Imaging of the entire abdomen and pelvis to evaluate for infectious or inflammatory processes of the abdominal viscera and solid organs, abdominal and pelvic neoplasms, and screen for ischemic or vascular etiologies is essential for prompt diagnosis and treatment. Often the first-line modality, CT quickly evaluates the abdomen/pelvis, providing for accurate diagnoses and management of patients with abdominal pain. Ultrasound and tailored MRI protocols may be useful as first-line imaging studies, especially in pregnant patients. In the postoperative abdomen, fluoroscopy may help detect anastomotic leaks/abscesses. While often performed, abdominal radiographs may not alter management. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Right Lower Quadrant Pain-Suspected Appendicitis.

Appendicitis remains the most common surgical pathology responsible for right lower quadrant (RLQ) abdominal pain presenting to emergency departments in the United States, where the incidence continues to increase. Appropriate imaging in the diagnosis of appendicitis has resulted in decreased negative appendectomy rate from as high as 25% to approximately 1% to 3%. Contrast-enhanced CT remains the primary and most appropriate imaging modality to evaluate this patient population. MRI is approaching CT in sensitivity and specificity as this technology becomes more widely available and utilization increases. Unenhanced MRI and ultrasound remain the diagnostic procedures of choice in the pregnant patient. MRI and ultrasound continue to perform best in the hands of experts. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Imaging of Mesenteric Ischemia.

Mesenteric ischemia is an uncommon condition resulting from decreased blood flow to the small or large bowel in an acute or chronic setting. Acute ischemia is associated with high rates of morbidity and mortality; however, it is difficult to diagnose clinically. Therefore, a high degree of suspicion and prompt imaging evaluation are necessary. Chronic mesenteric ischemia is less common and typically caused by atherosclerotic occlusion or severe stenosis of at least two of the main mesenteric vessels. While several imaging examination options are available for the initial evaluation of both acute and chronic mesenteric ischemia, CTA of the abdomen and pelvis is overall the most appropriate choice for both conditions. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Colorectal Cancer Screening.

This review summarizes the relevant literature regarding colorectal screening with imaging. For individuals at average or moderate risk for colorectal cancer, CT colonography is usually appropriate for colorectal cancer screening. After positive results on a fecal occult blood test or immunohistochemical test, CT colonography is usually appropriate for colorectal cancer detection. For individuals at high risk for colorectal cancer (eg, hereditary nonpolyposis colorectal cancer, ulcerative colitis, or Crohn colitis), optical colonoscopy is preferred because of its ability to obtain biopsies to detect dysplasia. After incomplete colonoscopy, CT colonography is usually appropriate for colorectal cancer screening for individuals at average, moderate, or high risk. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Nonvariceal Upper Gastrointestinal Bleeding.

Upper gastrointestinal bleeding (UGIB) remains a significant cause of morbidity and mortality with mortality rates as high as 14%. This document addresses the indications for imaging UGIB that is nonvariceal and unrelated to portal hypertension. The four variants are derived with respect to upper endoscopy. For the first three, it is presumed that upper endoscopy has been performed, with three potential initial outcomes: endoscopy reveals arterial bleeding source, endoscopy confirms UGIB without a clear source, and negative endoscopy. The fourth variant, "postsurgical and traumatic causes of UGIB; endoscopy contraindicated" is considered separately because upper endoscopy is not performed. When endoscopy identifies the presence and location of bleeding but bleeding cannot be controlled endoscopically, catheter-based arteriography with treatment is an appropriate next study. CT angiography (CTA) is comparable with angiography as a diagnostic next step. If endoscopy demonstrates a bleed but the endoscopist cannot identify the bleeding source, angiography or CTA can be typically performed and both are considered appropriate. In the event of an obscure UGIB, angiography and CTA have been shown to be equivalent in identifying the bleeding source; CT enterography may be an alternative to CTA to find an intermittent bleeding source. In the postoperative or traumatic setting when endoscopy is contraindicated, primary angiography, CTA, and CT with intravenous contrast are considered appropriate. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Pretreatment Staging of Colorectal Cancer.

Colorectal cancers are common tumors in the United States and appropriate imaging is essential to direct appropriate care. Staging and treatment differs between tumors arising in the colon versus the rectum. Local staging for colon cancer is less integral to directing therapy given radical resection is often standard. Surgical options for rectal carcinoma are more varied and rely on accurate assessment of the sphincter, circumferential resection margins, and peritoneal reflection. These important anatomic landmarks are best appreciated on high-resolution imaging with transrectal ultrasound or MRI. When metastatic disease is suspected, imaging modalities that provide a global view of the body, such as CT with contrast or PET/CT may be indicated. Rectal cancer often metastasizes to the liver and so MRI of the liver with and without contrast provides accurate staging for liver metastases. This article focuses on local and distant staging and reviews the appropriateness of different imaging for both variants. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Comparing Phlebotomy by Tail Tip Amputation, Facial Vein Puncture, and Tail Vein Incision in C57BL/6 Mice by Using Physiologic and Behavioral Metrics of Pain and Distress.

Tail tip amputation with minimal restraint is not widely used for mouse phlebotomy. In part, this infrequency may reflect policies influenced by tail tip amputation procedures for genotyping, which involve greater handling and tissue removal. To assess tail tip amputation with minimal restraint as a phlebotomy technique, we compared it with 2 more common methods: scruffing with facial vein puncture and lateral tail vein incision with minimal restraint. Blood glucose levels, audible and ultrasonic vocalizations, postphlebotomy activity and grooming behavior, open field and elevated plus maze behaviors, nest-building scores, and histologic changes at the phlebotomy site were evaluated. Mice in the facial vein phlebotomy group produced more audible vocalizations, exhibited lower postphlebotomy activity in the open field, and had more severe histologic changes than did mice in the tail incision and tail tip amputation groups. Facial vein phlebotomy did not affect grooming behavior relative to sham groups, whereas tail vein incision-but not tail tip amputation-increased tail grooming compared with that in control mice. Blood glucose levels, nest-building scores, and elevated plus maze behavior did not differ between groups, and no mice in any group produced ultrasonic vocalizations. Tail tip amputation mice did not perform differently than sham mice in any metric analyzed, indicating that this technique is a potentially superior method of blood collection in mice in terms of animal wellbeing.

Biochemical, Histopathologic, Physiologic, and Behavioral Effects of Nonsteroidal Antiinflammatory Drugs in Rainbow Trout (Oncorhynchus mykiss).

Because the number of fish being used in research is increasing rapidly, evaluating the analgesic and pathologic effects of NSAID in fish is essential. To determine the biochemical, histopathologic, physiologic and behavioral effects of 3 NSAID, 48 rainbow trout underwent anesthesia with tricaine methanesulfonate and exploratory celiotomy and were randomly assigned to receive flunixin (0.5 mg/kg IM), ketorolac (0.5 mg/kg IM), ketoprofen (2 mg/kg IM), or saline. Clinical pathologic variables were assessed 1 wk before surgery and 48 h after surgery. Histopathology was performed to evaluate the healing of the incision, tissue reaction at the injection site, and potential organ toxicity. Physiologic and behavioral parameters, including weight, feeding, opercular rate, and vertical position in the water, were measured to establish parameters for identifying pain in fish. The difference between the pre- and postoperative phosphorus concentrations was greater in the flunixin group than the saline group and was the only pathologic difference between treatment groups. Histopathology of incision site, injection site, and internal organs appeared normal, and healing did not appear to be inhibited by the drugs used. The physiologic parameters of opercular rate and weight were consistent and may be helpful in identifying pain in fish in future studies, whereas feeding and vertical position in the water were unhelpful as indicators of pain in this rainbow trout surgical model. Overall, according to clinical pathology and histopathology, the use of ketoprofen, ketorolac, and flunixin at the dosages used in this study lack negative effects in rainbow trout undergoing surgery.

Radiation-induced effects to nontarget abdominal and pelvic viscera.

Radiation injuries often occur during or after radiation therapy in the abdomen or pelvis. Although any organ in the abdomen or pelvis may be exposed to and injured by radiation therapy directed to a nearby organ, this article focuses on more frequently encountered imaging findings of inadvertent radiation damage. It is important for the radiologist to be familiar with the imaging appearances of inadvertent radiation damage to abdominopelvic viscera in order to sustain clinical relevance and not mistake radiation injuries for other entities.

A succinct rating scale for radiology report quality.

CONTEXT: Poorly written radiology reports are common among residents and are a significant challenge for radiology education. While training may improve report quality, a professionally developed reliable and valid scale to measure report quality does not exist. OBJECTIVES: To develop a measurement tool for report quality, the quality of report scale, with rigorous validation through empirical data. METHODS: A research team of an experienced psychometrician and six senior radiologists conducted qualitative and quantitative studies. Five items were identified for the quality of report scale, each measuring a distinct aspect of report quality. Two dedicated training sessions were designed and implemented to help residents generate high-quality reports. In a blinded fashion, the quality of report scale was applied to 804 randomly selected reports issued before (n = 403) and after (n = 401) training. Full-scale psychometrical assessments were implemented onto the quality of report scale's item- and scale-scores from the reports. The quality of report scale scores were correlated with report professionalism and attendings' preference and were compared pre-/post-training. RESULTS: The quality of report scale showed sound psychometrical properties, with high validity and reliability. Reports with higher quality of report scale score were more professional and preferable by attendings. Training improved the quality of report scale score, empirically validating the quality of report scale further. CONCLUSION: While succinct and practitioner friendly, the quality of report scale is a reliable and valid measure of radiology report quality and has the potential to be easily adapted to other fields such as pathology, where similar training would be beneficial.

Emergent and nonemergent nonbowel torsion: spectrum of imaging and clinical findings.

Although bowel torsion is more commonly described in the medical literature, torsion can affect various organs within the chest, abdomen, and pelvis, including the testes, ovaries, gallbladder, spleen, heart, and pulmonary lobes. A structural abnormality such as a mass (a "lead point") that promotes twisting around a vascular pedicle often predisposes an organ or other anatomic structure to torsion. Radiologists play a central role in detecting torsion, identifying the anatomy involved, and triaging patients for either emergent surgical intervention, which may be critical for organ salvage, or conservative management. Imaging findings that are suggestive or indicative of emergent torsion include an ectopic location and enlargement or edema of part or all of an organ, decreased blood flow at color Doppler ultrasonography, and a twisted vascular pedicle. Blood flow to an organ is quickly compromised by the constriction of vessels within the twisted pedicle, and ischemia may result; a delay in diagnosis and surgical treatment can lead to complications such as infarction, hemorrhagic necrosis, and abscess. By contrast, torsion of mobile fatty structures such as testicular appendages, epiploic appendages, omental fat, and pericardial fat pads, although it may produce pain mimicking that in an emergent condition, requires only conservative management. Imaging features of this nonemergent condition include a fatty mass, which is usually located alongside the colon when torsion involves the omentum or an epiploic appendage, with associated inflammatory stranding and tenderness at palpation. The radiologist should be familiar with these manifestations of nonemergent torsion to prevent unnecessary surgical intervention.

Teratomas: a multimodality review.

Germ cell tumors (GCTs) may occur in both children and adults and include a broad array of histologic subtypes, such as teratoma, seminoma (known as dysgerminoma in the ovary and germinoma in the pineal gland), choriocarcinoma, yolk sac tumor, embryonal cell carcinoma, and mixed GCT. In adults, GCTs occur most commonly in the gonads. In children, sacrococcygeal tumors predominate. Teratomas are a common form of GCT. They are defined histologically as containing tissues derived from all 3 germ cell layers: ectoderm, mesoderm (most teratomas contain fat, an imaging hallmark, which is a mesodermal derivative), and endoderm. Teratomas are also classified as mature or immature, depending on the degree of differentiation of its components, and in adults, immature tumors are more likely to exhibit malignant behavior.