Chronic recurrent multifocal osteomyelitis

Chronic recurrent multifocal osteomyelitis (CRMO) is a clinical entity distinct from bacterial osteomyelitis. It occurs mainly in children and adolescents and is characterized by a prolonged, fluctuating course with recurrent episodes of pain occurring over several years. CRMO is often multifocal and most often seen in tubular bones, the clavicle, and less frequently the spine and pelvic bones; other locations are rare. The radiographic appearance suggests subacute or chronic osteomyelitis. Histopathological and laboratory findings are nonspecific and bacterial culture is usually negative. CRMO is often diagnosed by exclusion of the two main differential diagnoses--bacterial infections and tumor--by assessing for a characteristic course and the findings by conventional radiography, if necessary supplemented by scintigraphy and/or magnetic resonance imaging (MRI). The MRI appearance of CRMO lesions in tubular bones and the spine is often rather characteristic and support the diagnosis. It is important to diagnose CRMO to avoid unnecessary diagnostic procedures and initiate an appropriate therapy.