Imaging of chronic recurrent multifocal osteomyelitis.

Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory disorder of children and young adults that is characterized by nonbacterial osteomyelitis. Patients typically present with multifocal bone pain secondary to sterile osseous inflammation, and the disease has a relapsing and remitting course. The cause of CRMO remains unclear, although the results of several studies have suggested a genetic component. The typical imaging findings of CRMO include lytic and sclerotic lesions in the metaphyses of long bones and the medial clavicles. Other common sites of disease are the vertebral bodies, pelvis, ribs, and mandible. CRMO is often bilateral and multifocal at presentation. Owing to the lack of a diagnostic test, CRMO remains a diagnosis of exclusion. Although generally a self-limiting disease, CRMO can have a prolonged course and result in significant morbidity. Radiologists can be the first to suggest this diagnosis given its characteristic radiographic appearance and distribution of disease. Radiologists should be familiar with the typical imaging findings of CRMO to prevent unnecessary multiple biopsies and long-term antibiotic treatment in children with CRMO. Copyright RSNA, 2009