Chronic Nonbacterial Osteomyelitis

Chronic nonbacterial osteomyelitis (CNO) is an autoinflammatory bone disorder of children and young adults. CNO is used as an umbrella term that fits a clinical spectrum of disease which may include a sporadic, single bone lesion; multifocal inflammatory lesions with a short duration (less than 6 months); to a chronic, recurrent form involving multiple lesions over a period of years [1]. The multifocal, relapsing form is best known as chronic multifocal recurrent osteomyelitis (CRMO). CRMO was first described in 1972 and has been described by a number of different terms: subacute and chronic symmetric osteomyelitis, subacute symmetric osteomyelitis, chronic multifocal symmetric osteomyelitis, chronic multifocal cleidometaphyseal osteomyelitis of childhood, chronic sclerosing osteitis, sclerosing osteomyelitis of Garré, sternocostoclavicular hyperostosis [1, 2]. As the disease process may begin or stay unifocal, the broader term CNO will be utilized in this manuscript.