Deficiency of interleukin-1-receptor antagonist syndrome: a rare auto-inflammatory condition that mimics multiple classic radiographic findings.

Deficiency of interleukin-1-receptor antagonist (DIRA) syndrome is a newly identified inflammatory disease of the skeleton and appendicular soft tissues presenting in early infancy that has yet to be reported in the radiology literature. The radiological manifestations of DIRA syndrome include multifocal osteitis of the ribs and long bones, heterotopic ossification and periarticular soft-tissue swelling. Thus, the pediatric radiologist should be made aware of this novel disease because its radiographic findings can mimic multiple other disease entities. With knowledge of the unique clinical presentation of DIRA syndrome and its multiple radiographic manifestations, the pediatric radiologist may be the first to suggest the correct diagnosis.