Inflammatory myofibroblastic tumor parieto-occipital bone

Inflammatory myofibroblastic tumor is a diverse group of lesions first described in lung and later on reported in various sites like stomach, bowel, spleen, bone. We report a case of inflammatory myofibroblastic tumor in a 30-year-old male who presented with a slowly progressive scalp swelling of two-year duration. Magnetic resonance imaging showed an intradiploic well enhancing lesion in parietal and occipital bone, isointense on T1 weighted images and hypo intense on T2 weighted images with dural enhancement. On histopathological examination, the lesion was composed of variable admixture of spindle cells with eosinophilic cytoplasm and inflammatory cells comprising of plasma cells and lymphocytes. The lesion was infiltrating the underlying dura. The spindle cells showed strong positivity for smooth muscle actin on immunohistochemistry. A final histopathologic diagnosis of inflammatory myofibroblastic tumor was rendered.