Proliferative myositis in a child

A case of proliferative myositis in the lumbar paraspinal muscles in a 14-y ear-old boy is presented. Imaging investigations including plain radiograph , ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), b one scan and positron emission tomography (PET) were suggestive of an infla mmatory process such as myositis ossificans, The diagnosis was made by inci sional biopsy. More pronounced edema, more muscle fiber necrosis and a high er cellularity were found compared to adult cases, The karyotype of the les ion was normal. Clinically, the mass disappeared spontaneously. After 24 mo nths, asymptomatic bridging ossification between the third and fourth lumba r vertebrae was noted.