CD43-positive, EWSR1::FLI1 -rearranged Soft Tissue Sarcoma in a Pediatric Patient With History of B-Cell Acute Lymphoblastic Leukemia.

Ewing sarcoma is a small round blue cell tumor typically characterized by an EWSR1 rearrangement and expression of CD99 and NKX2.2, without expression of hematopoietic markers such as CD45. CD43 is an alternative hematopoietic immunohistochemical marker often utilized in the workup of these tumors and its expression typically argues against Ewing sarcoma. We report a 10-year-old with history of B-cell acute lymphoblastic leukemia presenting with an unusual malignant shoulder mass with variable CD43 positivity, but with an EWSR1::FLI1 fusion detected by RNA sequencing. Her challenging workup highlights the utility of next-generation DNA-based and RNA-based sequencing methods in cases with unclear or conflicting immunohistochemical results.

Pediatric Tumor Management: Current and Controversial.

Bone and soft-tissue tumors are common in the pediatric population. It is important to be familiar with the appropriate workup, principles of biopsy, differences between unicameral and aneurysmal bone cysts, and principles of managing pathologic fractures in children. The management approach to pediatric soft-tissue masses and some of the recent advances in the field warrant discussion.

Management of Pediatric Type I Open Fractures in the Emergency Department or Operating Room: A Multicenter Perspective.

BACKGROUND: The management of pediatric type I open fractures remains controversial. The aim of this study is to compare outcomes in type I open fractures managed with superficial wound debridement and antibiotics in the emergency department (ED) (nonoperative management) to patients managed with operative debridement and antibiotics (operative management). METHODS: A multicenter retrospective review was performed of all pediatric type I open forearm, wrist, and tibia fractures treated at 4 high volume pediatric centers between 2000 and 2015. Patients with multiple traumatic injuries, immunocompromised patients, or those without final radiographs indicating healing were excluded. RESULTS: In total, 219 patients met inclusion criteria. A total of 170 fractures were treated operatively (77.6%), 49 fractures were treated nonoperatively (22.4%). There was 1 infection in the nonoperative group (2.0% infection rate), and no infections in the operatively managed group (P=0.062). Cefazolin was the most commonly administered antibiotic (88.1% of patients). Duration of hospital-administered antibiotics was significantly different, with a mean of 10.9 hours in the nonoperative group and 41.6 hours in the operative group (P<0.001). Length of stay averaged 16.3 hours for nonoperative patients and 48.6 hours for the operatively treated patients (P<0.001). In the nonoperative group, 44/49 had documented superficial wound debridement in the ED utilizing, on an average, 1500 mL of irrigant. There were 10 other complications, 9 in the operative group (5.4%) and 2 in the nonoperative group (4.1%, P=0.107), including 2 compartment syndromes and 1 acute carpal tunnel syndrome all requiring immediate surgical release (1.8%) in the operative group. CONCLUSIONS: There was no significant difference in infection rate or complication rate in those managed with antibiotics and operative debridement versus those managed with superficial wound debridement and antibiotics in the ED. Consideration should be given to the similar safety profiles for these 2 treatment modalities when managing pediatric patients with type I open fractures. LEVEL OF EVIDENCE: Level III.

Computational fluid dynamics modeling aiding surgical planning in a toddler with Parkes Weber syndrome.

Parkes Weber syndrome is a fast-flow and slow-flow vascular anomaly with limb overgrowth that can lead to congestive heart failure and limb ischemia. Current management strategies have focused on symptom management with focal embolization. A pediatric case with early onset heart failure is reported. We discuss the use of computational fluid dynamics (CFD) modeling to guide a surgical management strategy in a toddler with an MAP2K1 mutation.

Defining the volume of consultations for musculoskeletal infection encountered by pediatric orthopaedic services in the United States.

OBJECTIVE: Adequate resources are required to rapidly diagnose and treat pediatric musculoskeletal infection (MSKI). The workload MSKI consults contribute to pediatric orthopaedic services is unknown as prior epidemiologic studies are variable and negative work-ups are not included in national discharge databases. The hypothesis was tested that MSKI consults constitute a substantial volume of total consultations for pediatric orthopaedic services across the United States. STUDY DESIGN: Eighteen institutions from the Children's ORthopaedic Trauma and Infection Consortium for Evidence-based Study (CORTICES) group retrospectively reviewed a minimum of 1 year of hospital data, reporting the total number of surgeons, total consultations, and MSKI-related consultations. Consultations were classified by the location of consultation (emergency department or inpatient). Culture positivity rate and pathogens were also reported. RESULTS: 87,449 total orthopaedic consultations and 7,814 MSKI-related consultations performed by 229 pediatric orthopaedic surgeons were reviewed. There was an average of 13 orthopaedic surgeons per site each performing an average of 154 consultations per year. On average, 9% of consultations were MSKI related and 37% of these consults yielded positive cultures. Finally, a weak inverse monotonic relationship was noted between percent culture positivity and percent of total orthopedic consults for MSKI. CONCLUSION: At large, academic pediatric tertiary care centers, pediatric orthopaedic services consult on an average of ~3,000 'rule-out' MSKI cases annually. These patients account for nearly 1 in 10 orthopaedic consultations, of which 1 in 3 are culture positive. Considering that 2 in 3 consultations were culture negative, estimating resources required for pediatric orthopaedic consult services to work up and treat children based on culture positive administrative discharge data underestimates clinical need. Finally, ascertainment bias must be considered when comparing differences in culture rates from different institution's pediatric orthopaedics services, given the variability in when orthopaedic physicians become involved in a MSKI workup.

Soft Tissue Sarcoma Response to Two Cycles of Neoadjuvant Chemotherapy: A Multireader Analysis of MRI Findings and Agreement with RECIST Criteria and Change in SUVmax.

RATIONALE AND OBJECTIVES: When soft tissue sarcomas are treated with neoadjuvant chemotherapy, the number of cycles of chemotherapy is usually dependent on the tumor's initial response. Popular methods to assess tumor response include Response Evaluation Criteria in Solid Tumors (RECIST) criteria, which rely solely on tumor size, and maximum standardized uptake value (SUVmax) reduction in positron emission tomography (PET), which requires an expensive and high radiation test. We hypothesized that contrast-enhanced magnetic resonance imaging (MRI) may offer a good alternative by providing additional information beyond tumor size. MATERIALS AND METHODS: Following IRB approval, a retrospective review identified patients with soft tissue sarcomas who underwent both PET and MRI before and after two cycles of neoadjuvant chemotherapy. Five readers independently examined the MRI exams for: changes in size, T2 or T1 signal, necrosis and degree of enhancement. Readers then made a subjective binary assessment of tumor response to therapy. Each reader repeated the anonymized randomized reading at least 2 weeks apart. 18 F-FDG PET exams were interpreted by a nuclear medicine specialist. The maximum standardized uptake values (SUVmax) for pre and post-chemotherapy exams were compared. Intra- and inter-reader agreement was assessed using Cohen's kappa and Light's kappa, respectively. . RESULTS: Twenty cases were selected for this multireader study, of which 9 (45%) were responders and 11 were nonresponders by SUVmax. Using all MRI criteria, 43% were classified as responders based on MRI and 1.5% were classified as responders by RECIST criteria. Using PET as the reference, the sensitivity and the specificity of the MRI diagnosis for response using all findings were 50% and 63%, respectively. There was fair to moderate intrareader (kappa = 0.37) and inter-reader (kappa = 0.48) agreement for the MRI diagnosis of response. None of the individual MRI signal characteristics were significantly different between the PET responders and nonresponders. Additionally, no MRI findings were significantly different between those with and without good clinical responses. CONCLUSION: By our assessment, there is a poor correlation between tumor response by RECIST criteria and PET SUVmax. In addition, varying MR features did not help in diagnosing tumor response. Imaging of tumor response remains a challenging area that requires further research.