CT and MRI diagnosis of osteosarcoma in paranasal sinus / 中华放射学杂志

ABSTRACT

Objective To study the CT and MRI findings of osteosarcoma in paranasal sinus and evaluate their clinical value.Methods All 9 cases of osteosarcoma were verified by histopathology.Imaging data were analyzed retrospectively.Results The lesion occurred in maxillary sinus in 5 cases,in ethmoid sinus in 3 cases and in sphenoid sinus in one case.Primary osteosarcoma was found in 7 cases.Secondary osteosarcoma occurred from fibrous dysplasia and ossifying fibroma each in one case.On CT,the involved areas revealed bony destruction associated with ill-defined and irregular soft tissue mass.The lesion showed heterogeneous density with minimal or massive tumor bone formation,cloud-like in 3 cases,ivory-like in 2 cases,spicule-like in 2 cases,cloud- and spicule -like in one case and spicule- and ivory-like in one case.Postcontrast CT showed mild to moderate inhomogeneous enhancement in 3 cases.On MR T_1 WI,the lesions showed hypointensity compared to brain in 5 cases and iso-intensity in 2 cases.On T_2WI,the lesions showed heterogeneous hyperintensity in 4 cases and isointensity in 3 cases with marked hypointense foci which corresponded to tumor bone on CT.Postcontrast MR imaging demonstrated moderate to marked inhomogeneous enhancement in these cases.MRI showed accurately the extent and associated changes of the lesions.The lesions invaded the orbit,pterygopalatine and infratemporal fossae,skull base and extensive craniofacial structures in 5,4,3 cases and 1 case,respectively.Conclusion CT is the optimal modality in showing tumor bone of osteosareoma in paranasal sinus.MRI can demonstrate optimally the invading extent of the lesions.Combined imaging modalities can provide more comprehensive information for diagnosis and therapy of osteosarcoma in paranasal sinus.