Imaging description

A 15-year-old boy presented with left-sided chest pain and a palpable chest wall mass. PA radiograph of the chest demonstrated osseous expansion and periosteal reaction in the left mid 8th rib and a large associated soft tissue mass (Fig. 91.1a). Axial contrast-enhanced CT of the chest demonstrated a heterogeneous soft tissue mass along the left chest wall. There was expansion, destruction, and periosteal reaction of the involved rib (Fig. 91.1b, c). An MRI of the abdomen, obtained to evaluate for metastases, was negative and also included the lower chest (Fig. 91.1d, e, f). This demonstrated a large heterogeneous T2 bright mass surrounding the left lower rib. The mass and marrow of the affected rib demonstrated restricted diffusion (bright signal on diffusion-weighted imaging [DWI] with dark signal on ADC map). Bone scan (not shown) did not demonstrate any metastases. Ewing’s sarcoma of the chest wall was suggested as the most likely diagnosis. Subsequent pathology defined the lesion as an undifferentiated sarcoma of the chest wall.