CT and multimodal imaging findings of primary orbital Ewing's sarcoma involving the middle cranial fossa: a case report

This report details the CT and MR imaging findings of a primary orbital Ewing's sarcoma case involving the middle cranial fossa in a 13-year old boy. CT showed an ill-circumscribed homogeneous soft-tissue density mass with needle-like bone reaction. On MRI, the mass showed homogeneous iso-intensity on T1WI, heterogeneous hyperintensity on T2WI, and marked homogeneous enhancement. Meanwhile, the mass was hyper-intense on DWI, and ADC value was 575×10-6 mm2/s. The mass showed as high rCBV and rCBF, prolonged MTT based on DCSPWI, and wash-out pattern of TIC derived from the DCE-MRI. Our case suggests that functional MRI modalities, including DWI, DSC-PWI or DCE-MR, could provide additional information for differential diagnoses. Both CT and MRI should be performed and comprehensively analyzed for limiting differential diagnoses, determining lesion extension and facilitating operative approach.