Purpose or Case Report: Learning Objectives:
-To recognize characteristic MRI features of chronic recurrent multifocal osteomyelitis (CRMO) that distinguish it from infectious osteomyelitis and malignancy
-To understand common imaging mimics including focal periphyseal edema zones, developmental variants, and physiologic bone marrow changes
-To appreciate the clinical-imaging discordance in CRMO and the role of whole-body MRI in detecting subclinical disease
Background: CRMO is a rare autoinflammatory bone disorder in children that poses diagnostic challenges due to overlapping features with infection, malignancy, and benign conditions. Early recognition of characteristic imaging patterns is crucial to avoid unnecessary biopsies, inappropriate antibiotic therapy, and diagnostic delays that may lead to skeletal complications.
Methods & Materials: This retrospective study included patients < 21 years diagnosed with CRMO between 2014 and 2024. Clinical presentation, lesion distribution, MRI and radiographic findings, and biopsy results were reviewed. Imaging mimics—including infection, malignancy, trauma, and focal periphyseal edema (FOPE) zones—were also evaluated for comparison.
Results: We reviewed 32 patients with CRMO (median age 10.2 years; 62.5% female) confirmed by Jansson criteria. Total 133 MRI lesions were identified (median 3 per patient). Key imaging features included multifocal metaphyseal bone marrow edema with STIR hyperintensity, T1 hypointensity, absence of abscess formation, and minimal periosteal reaction. Most common sites: femur/tibia (62.5%), sacrum (43.8%), clavicle (31.3%). Clinical symptoms localized to median 1 site while MRI revealed median 3 lesions, demonstrating substantial subclinical disease. Six patients experienced diagnostic delays of 2-9 years. Whole-body MRI (72% of cohort) detected additional lesions, particularly spinal involvement requiring treatment escalation.
Conclusions: Recognition of CRMO's characteristic multifocal metaphyseal pattern with clavicular predilection helps distinguish it from mimics. Awareness of clinical-imaging discordance supports early whole-body MRI implementation to detect subclinical disease and prevent long-term complications. This educational poster illustrates typical imaging findings, systematically reviews common mimics with comparative imaging features, and highlights practical pitfalls in diagnosis.