Purpose or Case Report: Chronic recurrent multifocal osteomyelitis (CRMO) is a relatively new autoinflammatory pediatric musculoskeletal diagnosis. It was first discovered by Giedion et al 1972, who described “an unusual form of multifocal bone lesions with subacute and chronic symmetrical osteomyelitis”. CRMO can be a problematic diagnosis due to its variable presentation. Clinical, laboratory, and imaging findings must be aggregated to arrive at a CRMO diagnosis. Imaging plays a central role in CRMO diagnosis and management. Typical imaging findings that are generally but not necessarily multifocal, and exhibit changes over time, are crucial to CRMO management plan.
Many pathologic entities can mimic CRMO because of its diverse clinical and imaging manifestations. These conditions include infectious processes such as septic arthritis and osteomyelitis, other inflammatory conditions such as psoriatic arthritis, metabolic disturbances such as rickets and scurvy, traumatic injuries such as acute fractures and osteonecrosis from repetitive microtrauma, neoplastic entities such as metastasis and lymphoma, and neoplastic-like entities like Langerhans cell histiocytosis. In our exhibit, we will review the classic imaging manifestations of CRMO and present a spectrum of lesions in which CRMO was an initial consideration, but ultimately proved to be a different pathology.

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Conclusions: Imaging plays a central role in diagnosis and management of CRMO. Many pathologic entities can mimic CRMO due to its protean manifestations, and a nuanced understanding of these mimics may assist the radiologist in both recognizing CRMO and generating differential considerations when the diagnosis remains unclear by imaging.