A primary inflammatory myofibroblastic tumor of the scapula in a child: imaging findings.

Abstract

Inflammatory myofibroblastic tumor (IMT) is an uncommon tumor characterized by inflammatory cell infiltration and differentiated myofibroblastic spindle cells. IMT was first described in the lung and retroperitoneum. Occurrence in bone has been well described in the maxilla and occasionally in the long bones in the adult population. We present a unique case of IMT arising primarily from the scapula in an 8-year-old patient, not described previously in the pediatric or adult literature. Imaging demonstrated an ill-defined and aggressive osteolytic lesion with cortical bone destruction associated with an important soft tissue component that extended into the adjacent muscles. Histologically, the tumor was composed of spindle and polygonal cells distributed in an inflammatory background with different proportions of plasma cells, lymphocytes, eosinophils and neutrophils. The absence of cellular atypia helped to differentiate this entity from malignant spindle cell tumors, and imaging could differentiate the tumor from the nontumoral inflammatory reaction.