鼻窦骨肉瘤的CT和MRI诊断

目的探讨鼻窦骨肉瘤的CT和MRI表现并评价2种影像检查方法的临床应用价值。方法回顾性分析9例经组织学证实的鼻窦骨肉瘤患者的影像资料。结果9例中发生于上颌窦5例，筛窦3例，蝶窦1例；原发7例，继发于骨纤维异常增殖症及骨化性纤维瘤各1例。CT表现：受累部位骨质破坏，伴有形态不规则软组织肿块，边界不清，密度不均匀，内散在数量及形态不一的肿瘤骨，呈棉絮状3例，象牙质状2例，放射状2例，棉絮状和放射状1例，放射状和象牙质状1例。3例增强后呈不均匀低至中度强化。MRI表现：病变与脑实质比较，在T1WI上表现为低信号5例，等信号2例；T2WI表现为高信号4例、等信号3例，内部信号不均匀，散在数量不等、形态不一的极低信号影，对应CT所见的肿瘤骨，增强后可见中度到显著不均匀强化。MRI清楚显示病灶大小及伴发的改变。病变侵犯眼眶5例，翼腭窝、颞下窝4例，颅底3例，广泛侵犯颅面部结构1例。结论CT是显示肿瘤骨较好的影像检查方法，MRI能够更清楚、准确显示病变侵犯的范围，两者结合可为该病诊断和治疗提供更全面的影像信息。

CT and MRI diagnosis of osteosarcoma in paranasal sinus

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 ethmmoid 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 T1WI, the lesions showed hypointensity compared to brain in 5 cases and iso-intensity in 2 cases. On T2WI, 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 osteosarcoma 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.