Tumor-Derived Retinoic Acid Regulates Intratumoral Monocyte Differentiation to Promote Immune Suppression.

The immunosuppressive tumor microenvironment (TME) is a major barrier to immunotherapy. Within solid tumors, why monocytes preferentially differentiate into immunosuppressive tumor-associated macrophages (TAMs) rather than immunostimulatory dendritic cells (DCs) remains unclear. Using multiple murine sarcoma models, we find that the TME induces tumor cells to produce retinoic acid (RA), which polarizes intratumoral monocyte differentiation toward TAMs and away from DCs via suppression of DC-promoting transcription factor Irf4. Genetic inhibition of RA production in tumor cells or pharmacologic inhibition of RA signaling within TME increases stimulatory monocyte-derived cells, enhances T cell-dependent anti-tumor immunity, and synergizes with immune checkpoint blockade. Furthermore, an RA-responsive gene signature in human monocytes correlates with an immunosuppressive TME in multiple human tumors. RA has been considered as an anti-cancer agent, whereas our work demonstrates its tumorigenic capability via myeloid-mediated immune suppression and provides proof of concept for targeting this pathway for tumor immunotherapy.

Leading an Organization in the 21st Century: The Importance of Environmental Sustainability, Social Responsibility, and Good Governance.

The concept of environmental sustainability, social responsibility, and good governance (ESG) is now well established in the corporate world and in for-profit organizations. However, it is not a concept that has reached medical and surgical association boardrooms in a meaningful way. It is important to define the concept of physician and corporate author expertise and objectives of ESG, provide a rationale for using ESG within orthopaedic organizations, and identify specific areas (primarily the "S" and the "G") where the American Academy of Orthopaedic Surgeons and other groups can align with this strategy.

Rising within the leadership of an orthopaedic society: learning from the presidents.

Orthopaedic societies, with their diverse membership from across the world, serve a mission to endorse the progress and innovation in the field of orthopaedics and traumatology with a focus on improving patient care, as well as to encourage and develop education, teaching and research. Such organizations, whether small or large, have been successful in meeting the professional, educational and training needs of its members. The past and future presidents of these societies share insights addressing their professional experiences, lessons learnt and their vision for future leaders of the field. The objective of this article is to summarize the thoughts of presidents of orthopaedic societies from around the globe and to inspire younger and aspiring members of the global orthopaedic fraternity.

Percutaneous doxycycline sclerotherapy in a horse with a mandibular aneurysmal bone cyst.

OBJECTIVE: To describe the use and outcome of sclerotherapy with intralesional doxycycline foam in a horse with a mandibular aneurysmal bone cyst. STUDY DESIGN: Case report. ANIMALS: Client-owned 1 year old Standardbred filly. METHODS: The horse presented for progressive mandibular swelling. A 10 mg/mL doxycycline foam was prepared for intralesional injection. Three doses were injected into the lesion under computed tomographic guidance at 6 and 15 weeks after initial treatment. Volume reduction was monitored after each treatment with 3D volumetric rendering and region of interest segmentation using commercially available software. RESULTS: The volume of the lesion decreased from 458.7455 cm3 before treatment, to 363.3101 cm3 at 6 weeks, 273.5855 cm3 at 15 weeks, and 247.2316 cm3 6 months later, resulting in a total reduction of 54% of the initial volume. Bone formation was noted in the lesion. No adverse effects related to doxycycline foam injections were noted. The mandibular swelling was resolved after treatment. CONCLUSION: Intralesional doxycycline sclerotherapy was shown to be efficacious in reducing the volume of the aneurysmal bone cyst in the horse presented in this report. There was complete resolution of mandibular swelling with no side effects related to the intralesional injections.

Radiotherapy Remains Underused in the Treatment of Soft-Tissue Sarcomas: Disparities in Practice Patterns in the United States.

BACKGROUND: Practice patterns of radiation therapy (RT) use for soft-tissue sarcoma (STS) remain quite variable, despite clinical practice guidelines recommending the addition of RT to surgery for patients with high-grade STS, particularly for larger tumors. Using the National Cancer Database (NCDB), we assessed patterns of overall RT use, neoadjuvant versus adjuvant treatment, and specific RT modalities in this population. PATIENTS AND METHODS: Patients aged ≥18 years with stage II/III STS in 2004 through 2015 were identified from the NCDB. Patterns of care were assessed using multivariable logistic regression analysis. RESULTS: Of 27,426 total patients, 11,654 (42%) were treated with surgery alone versus 15,772 (58%) with RT in addition to surgery, with no overall increase in RT use over the study period. Notable clinical predictors of receipt of RT included tumor size (>5 cm), grade III, and tumors arising in the extremities. Conversely, female sex, older age (≥70 years), Black race, noncommercial insurance coverage, farther distance to treatment, and poor performance status were negative predictors of RT use. Of those receiving RT, 27% were treated with neoadjuvant RT and 73% with adjuvant RT. The proportion of those receiving neoadjuvant RT increased over time. Relevant factors associated with neoadjuvant RT included treatment at academic centers, larger tumor size, and extremity tumors. Of those who received RT with a modality specified as either intensity-modulated RT (IMRT) or 3D conformal RT (3DCRT), 61% were treated with IMRT and 39% with 3DCRT. The proportion of patients treated with IMRT increased over time. Relevant factors associated with IMRT use included treatment at academic centers, commercial insurance coverage, and larger and nonextremity tumors. CONCLUSIONS: Although use of neoadjuvant RT and IMRT has increased over time, a significant number of patients with STS are not receiving adjuvant or neoadjuvant RT. Our findings also note potential sociodemographic disparities and highlight the concern that not all patients with STS are being equally considered for RT.

How Does Representation of Women on Editorial Boards Compare Among Orthopaedic, General Surgery, and Internal Medicine Journals?

BACKGROUND: Women have historically been underrepresented as editors of peer-reviewed medical journals. Studies have demonstrated that there are differences in editorial board reviewer behavior based on gender, suggesting that greater representation by women on editorial boards may improve the quality and diversity of the review process. Therefore, the current representation of women on the editorial boards of orthopaedic journals, particularly compared with peer-reviewed surgical and medical journals, is of interest. QUESTIONS/PURPOSES: (1) What is the representation of women as members of editorial boards of prominent orthopaedic surgery journals? (2) How does it compare with representation on the editorial boards of journals in general surgery and internal medicine? METHODS: The top 15 journals with a strong clinical emphasis based on Impact Factor (Clarivate Analytics) calculated by the 2018 Journal Citation Reports were identified for orthopaedic surgery, general surgery (and all general surgical subspecialties), and internal medicine (with representative internal medicine subspecialties). Clinical publications with their primary editorial office located in the United States led predominantly by physicians or basic scientists were eligible for inclusion. The members of an editorial board were identified from the journals' websites. The gender of editors with gender-neutral names (and editors whose gender we considered uncertain) was identified by an internet search for gender-specific pronouns and/or pictures from an institutional profile. Fisher exact tests and t-tests were used to analyze categorical and continuous variables, respectively. Significance was set at p < 0.05. RESULTS: Of the editors analyzed, women made up 9% (121 of 1383) of editorial boards in the orthopaedic journals with the highest Impact Factors, compared with 21% (342 of 1665) of general surgery journals (p < 0.001) and 35% (204 of 587) of internal medicine journals (p < 0.001). The overall mean composition of editorial boards of orthopaedic journals was 10% ± 8% women, compared with that of general surgery, which was 19% ± 6% women (p < 0.001), and that of internal medicine, which was 40% ± 19% women (p < 0.001). CONCLUSION: Women make up a smaller proportion of editorial boards at orthopaedic surgery journals than they do at general surgery and internal medicine journals. However, their representation appears to be comparable to the proportion of women in orthopaedics overall (approximately 6%) and the proportion of women in academic orthopaedics (approximately 19%). Ways to improve the proportion of women on editorial boards might include structured mentorship programs at institutions and personal responsibility for championing mentorship and diversity on an individual level. CLINICAL RELEVANCE: Increasing representation of women on editorial boards may improve the diversity of perspectives and quality of future published research, generate visible role models for young women considering orthopaedics as a career, and improve patient care through enriching the diversity of our specialty.

Magnetic resonance imaging features of intra-articular tenosynovial giant cell tumor in children.

BACKGROUND: Magnetic resonance imaging (MRI) plays a critical role in disease characterization of intra-articular tenosynovial giant cell tumor. OBJECTIVE: To characterize the MRI features of intra-articular tenosynovial giant cell tumor in children with respect to disease subtype and anatomical location. MATERIALS AND METHODS: This retrospective study included children with tenosynovial giant cell tumor who underwent preoperative MRI between January 2006 and May 2020. Two radiologists reviewed each examination to determine disease subtype, signal intensities and the presence of an effusion, osseous changes, chondromalacia, juxtacapsular disease and concomitant joint involvement. Fisher exact, Mann-Whitney U, and Kruskal-Wallis H tests were used to compare findings between subtypes and locations. RESULTS: Twenty-four children (16 girls, 8 boys; mean age: 13.1±3.8 years) with 19 knee and 5 ankle-hindfoot tenosynovial giant cell tumor had either diffuse (n=15) or localized (n=9) disease. An effusion (P=0.004) was significantly more common with diffuse than localized disease. There was no significant difference in MRI signal (P-range: 0.09-1) or other imaging findings (P-range: 0.12-0.67) between subtypes. Children with knee involvement were significantly more likely to present with diffuse disease while those with ankle-hindfoot involvement all presented with focal disease (P=0.004). Juxtacapsular (n=4) and concomitant proximal tibiofibular joint involvement (n=5) were observed with diffuse disease in the knee. Erosions (P=0.01) were significantly more common in the ankle than in the knee. CONCLUSION: In our study, diffuse tenosynovial giant cell tumor was more common than localized disease, particularly in the knee where juxtacapsular and concomitant proximal tibiofibular joint disease can occur.

Top Tips for an Orthopaedic Surgeon's Practice.

As orthopaedic surgeons become more specialized, it is important that they remain up to date in the diagnosis and management of common orthopaedic problems. These can include conditions encountered in the clinic and/or on call. It is important that practicing surgeons stay abreast of recognition and management of problems, not only for the patients, but also to avoid commonly missed conditions or less-than-optimal treatment. The orthopaedic surgeon should be aware of the top tips in multiple disciplines, including orthopaedic oncology, hand, and trauma.

Multi-institutional analysis of stereotactic body radiotherapy for sarcoma pulmonary metastases: High rates of local control with favorable toxicity.

BACKGROUND/OBJECTIVES: Oligometastatic sarcoma pulmonary metastases (PM's) are traditionally treated with resection and/or chemotherapy. We hypothesize that stereotactic body radiotherapy (SBRT) is an effective, safe alternative to surgery that can achieve excellent local control (LC) with a favorable toxicity profile. METHODS: Patients treated with SBRT for sarcoma PM's from 2011 to 2016 at Massachusetts General Hospital and the University of Pennsylvania were included. Median dose was 50 Gy. Patients underwent computed tomography (CT) or positron emission tomography/CT Q3 months post-SBRT. RESULTS: 44 patients with 56 separate PM's were treated with SBRT. Median age was 59 (range 19-82). 82% received prior chemotherapy, 66% had prior pulmonary resections (range, 1-5 resections), and 32% received prior thoracic radiotherapy. Median lesion size was 2.0 cm (range, 0.5-8.1 cm). Median follow-up was 16 months and 25 months for patients alive at last follow-up. Overall survival at 12 and 24 months was 74% (95% confidence interval [CI], 67%-81%) and 46% (95% CI, 38%-55%). LC at 12 and 24 months was 96% (95% CI, 93%-98%) and 90% (95% CI, 84%-96%). LC and overall survival did not differ based on age, gender, histology, fractionation, lesion location, or size (P > .05). Three developed Common Terminology Criteria for Adverse Events version 4 grade-2 chest-wall toxicities; one had grade-2 pneumonitis. CONCLUSIONS: In the first multi-institutional series on SBRT for sarcoma PM's, SBRT has excellent LC and is well-tolerated. SBRT should be considered as an alternative/complement to resection.

Limb Salvage and Reconstruction Options in Osteosarcoma.

Advances in chemotherapy, sophisticated imaging, and surgical techniques over the last few decades have allowed limb-salvage surgery (LSS) to become the preferred surgical treatment for bone sarcomas of the extremities. The goal of LLS is to maximize limb functionality to allow for the maintenance of quality of life without compromising overall survival and tumor local recurrence rates. Today, limb-salvage procedures are performed on 80-95% of patients with extremity osteosarcoma, and the 5-year survival rate in extremity osteosarcoma patients is now 60-75%.This chapter will focus on LSS for extremity osteosarcoma. Common types of surgical reconstruction techniques including endoprostheses, intercalary or osteoarticular allografts, vascularized fibular autografts, and allograft prosthetic composites (APC), and their complications such as infection, local recurrence, graft fracture, implant failure, and nonunion will be discussed in detail. Anatomic locations of lesions discussed include the proximal femur, distal femur, proximal tibia, distal tibia, proximal humerus, distal humerus, and forearm bones.

Women in Orthopaedics: How Understanding Implicit Bias Can Help Your Practice.

Women comprise approximately 50% of medical students; however, only 14% of current orthopaedic residents are women. There are many factors that contribute to the reluctance of female medical students to enter the field including limited exposure to musculoskeletal medicine during medical school, negative perception of the field, lack of female mentors, barriers to promotion, and acceptance by senior faculty. Diversity in orthopaedics is critical to provide culturally competent care. Two pipeline programs, the Perry Initiative and Nth Dimensions, have successful track records in increasing female and underrepresented minorities in orthopaedic surgery residency training. Recognizing and combating implicit bias in orthopaedics will improve recruitment, retention, promotion, and compensation of female orthopaedic surgeons. The purpose of this chapter is to provide an overview of the current status of women in orthopaedics, describe ways to improve diversity in the field, and make surgeons aware of how implicit bias can contribute to discrepancies seen in orthopaedic surgery, including pay scale inequities and women in leadership positions.

A Modification of an Established Method of Intercalary Extremity Bone Defect Reconstruction: The "Hemi-Capanna" Technique.

BACKGROUND: Skeletal reconstruction of segmental defects of the appendicular skeleton is among the most challenging tasks in reconstructive surgery. A popular method of reconstruction of large osseous defects is the combination of massive allografts and vascularized bone transfer. We present and discuss our experience with a modification of the traditional Capanna technique in which the allograft is split in half longitudinally to provide for more space for postoperative fibula hypertrophy. METHODS: Patients who underwent reconstruction of segmental intercalary defects of the tibia using our modified technique were retrospectively identified. The following parameters were retrieved: patient age, race, sex, length of skeletal defect, recipient vessels, type of microsurgical anastomosis, union rate, complication rate, ambulation (yes/no), and follow-up (in months). RESULTS: Two male patients underwent reconstruction of the tibia via the modified "hemi-Capanna" technique. The tibia defect measured 12 and 13 cm, respectively. No intraoperative or postoperative complications were encountered. Osseous union was obtained in both patients who are both ambulatory. CONCLUSION: The hemi-Capanna technique not only leaves more room for hypertrophy of the vascularized fibula, but also simplifies the technique of combining an allograft with vascularized bone transfer in reconstructions of segmental skeletal defects of the appendicular skeleton.

Concordance between fine-needle aspiration and core biopsies for osseous lesions by lesion imaging appearance and CT attenuation.

OBJECTIVES: To compare the concordance between fine-needle aspiration and core biopsies for osseous lesions by lesion imaging appearance and CT attenuation. MATERIALS AND METHODS: Retrospective review of 215 FNAs of osseous lesions performed in conjunction with core biopsy at our institution over a 6-year period (2011-2016). FNAs were interpreted independently of core biopsies. We assessed if FNA in conjunction with core biopsy increased diagnostic accuracy compared to core biopsy alone. We also calculated the concordance between FNA and core biopsy by lesion appearance, lesion CT attenuation, lesion histology, lesion location and FNA needle gauge size. RESULTS: Core biopsy alone provided the diagnosis in 207/215 cases (96.3%), however, the FNA provided the diagnosis in the remaining 8/215 cases (3.7%) where the core biopsy was non-diagnostic. There were 154 (71.6%) lytic lesions, 21 (9.8%) blastic lesions, 25 (11.6%) mixed lytic and blastic lesions and 15 (7.0%) lesions that were neither lytic nor blastic. The concordance between FNA and core biopsy for lytic osseous lesions (136/154 cases, 88.3%) was statistically significantly higher than that for blastic osseous lesions (13/21 cases, 61.9%) [P = 4.2 × 10-3; 95% CI (0.02, 0.50)]. The concordance between FNA and core biopsy was higher for low-attenuation- (110/126) than high-attenuation (58/77) lesions (P = 0.028). The concordance between FNA and core biopsy was also higher for metastases (102/119 cases, 85.7%) than non-metastases (78/96, 81.3%) [P = 0.487; 95% CI (- 0.15, 0.065)]. There was no difference in the rate of concordance between FNA and core biopsy by lesion location or FNA needle gauge size (P > 0.05). CONCLUSION: FNA with core biopsy increases diagnostic rate compared to core biopsy alone or FNA alone. The concordance between FNA and core biopsy is higher for lytic lesions than for blastic lesions; and higher for low-attenuation lesions than for high-attenuation lesions.

Atypical retiform hemangioendothelioma arising in a patient with Milroy disease: a case report and review of the literature.

Retiform hemangioendothelioma (RH) is a rare vascular neoplasm with a high rate of local recurrence and low metastatic potential. We describe an unusual case of RH in a 45-year-old patient with Milroy disease, with a prominent solid component diffusely involving a chronic lymphedematous leg. This case is consistent with the postulated relationship between lymphedema and vascular neoplasms developing as a result of local immune dysfunction, and highlights the need to closely monitor patients with Milroy disease for pathologic changes. Our case highlights a unique example of RH with atypical features. There are several noteworthy unusual clinical and histologic findings including diffuse involvement of an entire limb, solid component with cytologic atypia, D2-40 expression, and first-time-reported association with Milroy disease. Given the atypical histologic presentation of cytologic atypia, solid areas and atypical immunohistochemical profile with D2-40 positivity, this case could cause diagnostic difficulty, especially in the setting of such a broad clinical differential.

What's Wrong With the Bone? An Overview of Metabolic and Neoplastic Bone Conditions.

The evaluation of any orthopaedic condition often begins with obtaining plain radiographs. Fortuitously, plain radiographs provide surgeons with direct information on the biologic activity and, therefore, the aggressiveness of any bone lesion. More advanced imaging modalities may fail to elucidate the problem and may even obscure the diagnosis. The accurate interpretation of the aggressiveness of a bone lesion on plain radiographs is the first step in establishing a differential diagnosis for any bone lesion and, often, may result in a correct diagnosis without the need for additional imaging studies. A thorough understanding of the radiographic classification of bone lesions will allow surgeons to accurately diagnose and manage metabolic bone disease, benign bone lesions, and malignant bone lesions.

Ultrasound-Guided Therapy for Knee and Foot Ganglion Cysts.

The present study evaluated the effectiveness of ultrasound-guided aspiration/injection of ganglion cysts in the lower extremities (knee and foot) that required referral to the radiology department for precise localization. The present study is the first series to describe such results. The study population consisted of 15 patients who had undergone treatment from April 2012 to January 2015. Follow-up was by telephone survey, which was performed at a mean of 15 ± 6 months after treatment. Almost 90% of patients experienced immediate improvement in symptoms (mostly pain), and 77% of these patients had not experienced a recurrence of symptoms at a mean follow-up time of 14 ± 6 months. In conclusion, ultrasound-guided therapy is a safe and potentially effective treatment for most cases of symptomatic lower extremity ganglion cysts.

Efficacy and safety of stereotactic body radiation therapy for the treatment of pulmonary metastases from sarcoma: A potential alternative to resection.

BACKGROUND/OBJECTIVES: Oligometastatic sarcoma pulmonary metastases (PM) are typically treated with resection and/or chemotherapy. We hypothesize that stereotactic body radiotherapy (SBRT) can be an alternative to surgery that can achieve high rates of local control (LC) with limited toxicity. METHODS: Thirty consecutive sarcoma patients received SBRT to 39 PM's from 2011 to 2015 at two university hospitals to a median dose of 50 Gy in 4-5 fractions with CyberKnife or linear accelerator. Patients underwent CT or PET/CT scans q3 months after SBRT. RESULTS: 77% received prior chemotherapy, 70% had 1-3 prior pulmonary resections, and 26% received prior thoracic radiotherapy. Median lesion size was 2.4 cm (range 0.5-8.1 cm). Median follow-up was 16 and 23 months for patients alive at last follow-up. At 12 and 24 months, LC was 94% and 86%, and OS was 76% and 43%. LC and OS did not differ by SBRT technique, fractionation regimen, lesion location, histology, or size (all P > 0.05). Three developed grade 2 chest-wall toxicity with no other grade ≥2 toxicities. CONCLUSIONS: This is the largest series on SBRT for sarcoma PM's and demonstrates that SBRT is well-tolerated with excellent LC across tumor locations and sizes. SBRT should be considered in these patients, and prospective studies are warranted. J. Surg. Oncol. 2016;114:65-69. © 2016 Wiley Periodicals, Inc.

Detection of soft-tissue sarcoma recurrence: added value of functional MR imaging techniques at 3.0 T.

PURPOSE: To determine the added value of functional magnetic resonance (MR) sequences (dynamic contrast material-enhanced [DCE] and quantitative diffusion-weighted [DW] imaging with apparent diffusion coefficient [ADC] mapping) for the detection of recurrent soft-tissue sarcomas following surgical resection. MATERIALS AND METHODS: This retrospective study was approved by the institutional review board. The requirement to obtain informed consent was waived. Thirty-seven patients referred for postoperative surveillance after resection of soft-tissue sarcoma (35 with high-grade sarcoma) were studied. Imaging at 3.0 T included conventional (T1-weighted, fluid-sensitive, and contrast-enhanced T1-weighted imaging) and functional (DCE MR imaging, DW imaging with ADC mapping) sequences. Recurrences were confirmed with biopsy or resection. A disease-free state was determined with at least 6 months of follow-up. Two readers independently recorded the signal and morphologic characteristics with conventional sequences, the presence or absence of arterial enhancement at DCE MR imaging, and ADCs of the surgical bed. The accuracy of conventional MR imaging in the detection of recurrence was compared with that with the addition of functional sequences. The Fisher exact and Wilcoxon rank sum tests were used to define the accuracy of imaging features, the Cohen κ and Lin interclass correlation were used to define interobserver variability, and receiver operating characteristic analysis was used to define a threshold to detect recurrence and assess reader confidence after the addition of functional imaging to conventional sequences. RESULTS: There were six histologically proved recurrences in 37 patients. Sensitivity and specificity of MR imaging in the detection of tumor recurrence were 100% (six of six patients) and 52% (16 of 31 patients), respectively, with conventional sequences, 100% (six of six patients) and 97% (30 of 31 patients) with the addition of DCE MR imaging, and 60% (three of five patients) and 97% (30 of 31 patients) with the addition of DW imaging and ADC mapping. The average ADC of recurrence (1.08 mm(2)/sec ± 0.19) was significantly different from those of postoperative scarring (0.9 mm(2)/sec ± 0.00) and hematomas (2.34 mm(2)/sec ± 0.72) (P = .03 for both). CONCLUSION: The addition of functional MR sequences to a routine MR protocol, in particular DCE MR imaging, offers a specificity of more than 95% for distinguishing recurrent sarcoma from postsurgical scarring.

Can MR imaging be used to predict tumor grade in soft-tissue sarcoma?

PURPOSE: To identify the magnetic resonance (MR) imaging features that can be used to differentiate high-grade from low-grade soft-tissue sarcoma (STS). MATERIALS AND METHODS: Institutional review board approval was obtained, and informed consent was waived. Patients with STS who had undergone MR imaging with T1-weighted, T2-weighted, and contrast material-enhanced sequences prior to neoadjuvant therapy and surgery were included retrospectively. Tumor grade (grades 1-3) was recorded from the histologic specimen for each STS. Images were evaluated by two observers for tumor size and MR features (signal intensity, heterogeneity, margin, and perilesional characteristics) on images obtained with each sequence. Descriptive statistics for low-grade (grade 1) and high-grade (grades 2 and 3) STS were recorded, and the accuracy of individual features was determined. A multivariate logistic regression model was developed to identify features that were independently predictive of a high-grade tumor. RESULTS: Ninety-five patients (48 female [mean age, 55.8 years; age range, 7-96 years] and 47 male [mean age, 55.3 years; age range, 1-87 years]) with STS (16 patients with grade 1 STS, 34 patients with grade 2 STS, and 45 patients with grade 3 STS) were included. High-grade STS differed from low-grade STS in size (>5 cm, P = .004), tumor margin (partly or poorly defined margin on T1-weighted images, P = .002; with other sequences, P < .001), internal signal intensity composition (heterogeneous signal intensity on T2-weighted images, P = .009), and peritumoral characteristics (peritumoral high signal intensity on T2-weighted images, P = .025; peritumoral enhancement on contrast-enhanced T1-weighted images, P < .001). The logistic regression model showed that peritumoral contrast enhancement is the strongest independent indicator of high-grade status (odds ratio, 13.6; 95% confidence interval: 2.9, 64.6). CONCLUSION: Among several MR imaging features that aid in the discrimination of high-grade from low-grade sarcomas, the presence of peritumoral contrast enhancement is a feature that may be solely used to diagnose high-grade STS.