Value of whole-body magnetic resonance imaging on progressive axial fusion and chronic non-bacterial osteomyelitis in pediatric Crohn’s disease: A case report

BACKGROUND Musculoskeletal manifestations are the most common extraintestinal manifestations of pediatric inflammatory bowel disease (IBD). However, the coexistence of Crohn’s disease (CD) with chronic non-bacterial osteomyelitis (CNO) and axial spondyloarthropathy creates a complex autoinflammatory phenotype that is challenging to manage and prone to severe structural damage. CASE SUMMARY We report the longitudinal course of a male patient with CD and progressive skeletal involvement. Despite sequential trials of adalimumab and infliximab (both discontinued due to anaphylaxis) and vedolizumab, the patient developed extensive cervical-occipital fusion and C6-C7 pseudoarthrosis. At age 15, whole-body magnetic resonance imaging (WB-MRI) was pivotal in identifying multifocal periphyseal bone marrow edema (BME) characteristic of concomitant CNO, which had been missed by targeted spinal imaging. Genetic testing identified a heterozygous nucleotide-binding oligomerization domain-containing protein 2 p.Leu762Phe variant. Following the diagnosis of this phenotype, treatment was intensified to tofacitinib and intravenous zoledronic acid. A follow-up WB-MRI at age 16 demonstrated a marked reduction in multifocal BME and resolution of active inflammatory lesions, though structural spinal fusion remained permanent. CONCLUSION This case suggests that in pediatric patients with IBD with refractory skeletal pain, clinicians might consider the possibility of overlapping autoinflammatory syndromes. While based on a single observation, the use of WB-MRI was instrumental in identifying subclinical lesions, assisting in the differentiation between active inflammation and permanent structural damage.