RESUMO
Chronic recurrent multifocal osteomyelitis (CRMO) is a rare disease. It is a non-microbial inflammatory bone affection that occurs more often in children with insidious onset and non specific presentation making diagnosis challenging. This study reports a case of CRMO with an unusual location. A 9-year-old child had a painful swelling over the medial side of clavicle with fixed mass. Radiographs showed osteolytic lesion on the medial part of clavicle extending to the acromioclavicular joint with soft tissue edema in magnetic resonance imaging (MRI). No inflammatory markers in biological exam. Needle biopsy, initially performed, suspected bone infection but children didn´t recover after 2 weeks of antibiotics. Surgical biopsy, histology sections were compatible with CRMO diagnosis. Children received a non steroid inflammatory drug with positive response, pain relief and decreasing of the clavicle swelling. CRMO should be suspected and biopsy is some time helpful in such unusual location.