Partially intraosseous schwannoma of the distal humerus with increased enhancement after biopsy: Radiologic-pathologic correlation.

Intraosseous schwannomas are rare benign tumors that most often occur at the mandible or sacrum. We present an unusual case of a bilobed schwannoma of the distal humerus with both intraosseous and extraosseous components. The extraosseous component was non-enhancing on initial MRI and enhanced on a subsequent MRI obtained after biopsy. We hypothesize that this change was attributable to decreased intra-tumoral pressure secondary to biopsy-related disruption of the tumor capsule.

Primary Septic Arthritis Among Children 6 to 48 Months of Age: Implications for PCR Acquisition and Empiric Antimicrobial Selection.

INTRODUCTION: Primary septic arthritis requires unique evaluation and treatment considerations for children in the 6- to 48-month age range because of the spectrum of identified pathogens and high rate of negative cultures. The purpose of this study is to evaluate primary septic arthritis in this age group in order to differentiate children with infection caused by Kingella kingae from those with other confirmed pathogens and those with no identified pathogen. METHODS: Preschool children who underwent multidisciplinary evaluation and treatment for septic arthritis between 2009 and 2019 were retrospectively studied. Three cohorts were established for comparison of clinical and laboratory features of primary septic arthritis: (1) confirmed K. kingae, (2) confirmed other pathogen, and (3) presumed (without identified pathogen). RESULTS: Among 139 children with septic arthritis, 40 (29%) were confirmed K. kingae, 29 (21%) other pathogen, and 70 (50%) presumed. Children with Kingella and those with presumed septic arthritis had significantly lower initial C-reactive protein (4.8 and 4.5 vs. 9.3 mg/dL) and fewer febrile hospital days (0.2 and 0.4 vs. 1.3 d) than children with other confirmed pathogens. Children with other pathogens had higher rates of bacteremia (38% vs. 0%) and positive joint fluid cultures (86% vs. 15%) than that of children with Kingella. The rate of polymerase chain reaction (PCR) acquisition was 38 of 40 (95.0%) Kingella cases, 18 of 29 (62.1%) other pathogen cases, and 33 of 70 (47.1%) presumed cases. CONCLUSIONS: K. kingae was the most commonly identified pathogen among 6-month to 4-year-old children. The Kingella and other identified pathogens in this study serve to guide empiric antimicrobial recommendations for this age range. Because of similarities between children with septic arthritis because of K. kingae and those with no identified pathogen, it is likely that an unrecognized burden of Kingella resides in culture negative cases, particularly if no PCR is sent. Systematic evaluation, including PCR acquisition, and a high index of suspicion for K. kingae are recommended to thoroughly evaluate septic arthritis in preschool children. LEVEL OF EVIDENCE: Level III-Retrospective cohort comparison.

Endobronchial Paraganglioma: AIRP Best Cases in Radiologic-Pathologic Correlation.

Editor's Note.-RadioGraphics continues to publish radiologic-pathologic case material selected from the American Institute for Radiologic Pathology (AIRP) "best case" presentations. The AIRP conducts a 4-week Radiologic Pathology Correlation Course, which is offered five times per year. On the penultimate day of the course, the best case presentation is held at the American Film Institute Silver Theater and Cultural Center in Silver Spring, Md. The AIRP faculty identifies the best cases, from each organ system, brought by the resident attendees. One or more of the best cases from each of the five courses are then solicited for publication in RadioGraphics. These cases emphasize the importance of radiologic-pathologic correlation in the imaging evaluation and diagnosis of diseases encountered at the institute and its predecessor, the Armed Forces Institute of Pathology (AFIP).

Pediatric Biliary Interventions in the Native Liver.

Biliary disease in infants and children frequently presents diagnostic and therapeutic challenges. Pediatric interventional radiologists are often involved in the multidisciplinary teams who care for these patients. This article reviews several notable causes of biliary disease in children who have not undergone liver transplantation, describes the role of percutaneous interventional procedures in managing these conditions, and details applicable biliary interventional techniques.