Why so low? An unusual case of myositis in a child.

BACKGROUND: Sarcoidosis is characterized by non-caseating epithelioid granulomas in various tissues throughout the body, most commonly the lung. Non-caseating granulomas may be seen in skeletal muscle, though typically asymptomatic and under-recognized. While rare in children, there is a need to better characterize the disease and its management. Here we present a 12-year-old female with bilateral calf pain who was ultimately found to have sarcoid myositis. CASE PRESENTATION: A 12-year-old female presented to rheumatology with significantly elevated inflammatory markers and isolated lower leg pain. MRI of the distal lower extremities demonstrated extensive bilateral myositis with active inflammation, atrophy, and to a lesser extent fasciitis. This distribution of myositis in a child garnered a broad differential requiring a systematic evaluation. Ultimately, muscle biopsy revealed non-caseating granulomatous myositis with perivascular inflammation, extensive muscle fibrosis, and fatty replacement of the muscle with a CD4+ T cell predominant, lymphohistiocytic infiltrate consistent with sarcoidosis. Review of histopathology from age 6 of an extraconal mass resected from her right superior rectus muscle further confirmed the diagnosis. She had no other clinical symptoms or findings of sarcoidosis. The patient improved significantly with methotrexate and prednisone, though flared again after self-discontinuation of medications and was subsequently lost to follow-up. CONCLUSION: This is the second reported case of granulomatous myositis associated with sarcoidosis in a pediatric patient, and the first to present with a chief complaint of leg pain. Increased knowledge of pediatric sarcoid myositis within the medical community will enhance recognition of the disease, improve the evaluation of lower leg myositis, and advance outcomes for this vulnerable population.

Radiologists' Diagnostic Performance in Differentiation of Rickets and Classic Metaphyseal Lesions on Radiographs: A Multicenter Study.

BACKGROUND. Despite evidence supporting the specificity of classic metaphyseal lesions (CML) for the diagnosis of child abuse, some medicolegal practitioners claim that CML result from rickets rather than trauma. OBJECTIVE. The purpose of this study was to evaluate radiologists' diagnostic performance in differentiating rickets and CML on radiographs. METHODS. This retrospective seven-center study included children younger than 2 years who underwent knee radiography from January 2007 to December 2018 and who had either rickets (25-hydroxyvitamin D level < 20 ng/mL and abnormal knee radiographs) or knee CML and a diagnosis of child abuse from a child abuse pediatrician. Additional injuries were identified through medical record review. Radiographs were cropped and zoomed to present similar depictions of the knee. Eight radiologists independently interpreted radiographs for diagnoses of rickets or CML, rated confidence levels, and recorded associated radiographic signs. RESULTS. Seventy children (27 girls, 43 boys) had rickets; 77 children (37 girls, 40 boys) had CML. Children with CML were younger than those with rickets (mean, 3.7 vs 14.2 months, p < .001; 89.6% vs 5.7% younger than 6 months; 3.9% vs 65.7% older than 1 year). All children with CML had injuries in addition to the knee CML identified at physical examination or other imaging examinations. Radiologists had almost perfect agreement for moderate- or high-confidence interpretations of rickets (κ = 0.92) and CML (κ = 0.89). Across radiologists, estimated sensitivity, specificity, and accuracy for CML for moderate- or high-confidence interpretations were 95.1%, 97.0%, and 96.0%. Accuracy was not significantly different between pediatric and nonpediatric radiologists (p = .20) or between less experienced and more experienced radiologists (p = .57). Loss of metaphyseal zone of provisional calcification, cupping, fraying, and physeal widening were more common in rickets than CML, being detected in less than 4% of children with CML. Corner fracture, bucket-handle fracture, subphyseal lucency, deformed corner, metaphyseal irregularity, and subperiosteal new bone formation were more common in CML than rickets, being detected in less than 4% of children with rickets. CONCLUSION. Radiologists had high interobserver agreement and high diagnostic performance for differentiating rickets and CML. Recognition that CML mostly occur in children younger than 6 months and are unusual in children older than 1 year may assist interpretation. CLINICAL IMPACT. Rickets and CML have distinct radiographic signs, and radiologists can reliably differentiate these two entities.

Prediction of quadriceps tendon-patellar bone autograft diameter in adolescents with 2-dimensional magnetic resonance imaging and anthropometric measures.

OBJECTIVES: This study evaluates the correlation between the bone end and soft tissue end of the quadriceps tendon-patellar bone autograft (QPA) size and pre-operative MRI measurements of the quadriceps tendon along sections to be included in the graft harvest in adolescents. We also assessed association between graft diameter and anthropometric measures (height, weight, and BMI), age, and sex. METHODS: Patients (10-18 years) who underwent QPA ACL reconstruction and had a pre-operative MRI were considered for inclusion. Age, height, and weight, tibial and femoral side graft diameter, and patellar bone block dimensions were collected. Using a pre-operative 2D sagittal plane MRI, we measured the quadriceps at 10-mm increments above the patella, up to 40 mm. We assessed correlation between the bone-end graft diameter and the AP measure at 10 mm above the patella, and correlation between the soft-tissue end graft diameter and the most proximal AP measure. RESULTS: A total of 103 patients were included. A significant correlation between the soft-tissue side graft diameter and most proximal AP measurement was observed (rs = 0.51; p < 0.001). However, measurements significantly underestimated the soft-tissue end graft diameter (9.6 ± 0.8 vs. 7.4 ± 1.1; p < 0.001). There was no correlation between the bone-end graft diameter and AP measurement 10 mm above the patella. Anthropometric measures were not associated with graft size. Skeletal maturity was associated with smaller graft size (p = 0.08). CONCLUSION: Soft-tissue end graft diameter is associated with the AP measure of the quadriceps at 20-40 mm above the superior pole of the patella.

Allergic bronchopulmonary aspergillosis: a unique presentation in a pediatric patient.

Infection by the Aspergillus species of fungus can result in a variety of clinically and radiographically unique pulmonary diseases. The specific disease manifested is most dependent upon the immunocompetency of the infected individual. Allergic bronchopulmonary aspergillosis (ABPA) is most commonly seen in patients with asthma and cystic fibrosis. Since its original description in 1952, much has been published describing the radiographic manifestations of this disease. In this article, we present the unusual case of a 13-year-old whose initial radiographic presentation was that of a dense lobar consolidation. Additionally, we highlight the contributory role of the radiologist in guiding the appropriate clinical work-up and treatment of this disease.