鼻眶部软骨肉瘤的CT和MRI诊断

目的探讨鼻眶部软骨肉瘤的CT和MRI表现,提高其诊断准确性.方法回顾性分析12例经病理证实的鼻眶部软骨肉瘤的影像学资料.结果12例中起源于鼻腔4例,鼻窦5例,眼眶3例.普通型软骨肉瘤8例,去分化型和间叶型软骨肉瘤各2例.CT表现：肿瘤呈卵圆形2例,分叶形6例,不规则形4例;内见散在点、环、结节、斑片状或不定型钙化;边界清楚9例,模糊3例;3例增强后呈不均匀低度强化.7例鼻软骨肉瘤出现骨质破坏,并侵犯周围结构;眼眶软骨肉瘤骨质破坏1例,并侵犯同侧额部.MRI表现：普通型和去分化型软骨肉瘤在T1WI上表现为低信号6例（与脑组织比较,以下同）,等信号4例,T2WI表现为高信号8例,等信号2例,信号不均匀,内见散在低信号区,增强后呈轻到中度不均匀强化,其中5例普通型软骨肉瘤边缘及间隔呈明显强化,内部不强化,呈斑驳状3例,蜂窝状2例;间叶型软骨肉瘤在T1、T2WI均呈等信号,增强后呈均匀和不均匀显著强化各1例.结论CT是鼻眶部软骨肉瘤诊断和鉴别的主要影像检查方法;典型间隔及边缘强化的MRI表现也能够提示诊断,MRI可更清楚、准确地显示病变侵犯的范围,为治疗提供可靠依据.

CT and MRI diagnosis of chondrosarcoma in sinonasal and orbital region

Objective To investigate the CT and MRI findings of chondrosarcoma in sinonasal and orbital region so as to promote the diagnostic accuracy. Methods All 12 cases of chondrosarcoma were verified by pathology. CT and MRI findings were analyzed retrospectively. Results The lesions occurred in sinonasal cavity in 9 cases and in orbit in 3 cases. Pathologically 8 cases were conventional chondrosarcoma, 2 dedifferentiated chondrosarcoma, and 2 mesenchymal chondrosarcoma. On CT, chondrosarcoma revealed oval shape in 2 cases, lobular shape in 6 cases and irregular shape in 4 cases. The lesion showed stippled, ring, nodular, patchy or amorphous calcification. Postcontrast CT showed mild inhomogeneous enhancement in 3 cases. Chondrosarcoma demonstrated well-defined margin in 9 cases and hazy margin in 3 cases. Sinonasal chondrosarcoma revealed bony destruction in 7 cases. Orbital chondrosarcoma showed bony erosion invading ipsilateral frontal region in one case. On MR T_1WI, conventional and dedifferentiated chondrosarcoma showed hypointense signal compared to brain in 6 cases and isointense signal in 4 cases. On T_2WI, the lesions showed heterogeneous hyperintense signal in 8 cases and isointense signal in 2 cases with marked hypointense foci. Postcontrast MR imaging demonstrated mild to moderate inhomogeneous enhancement in these cases, and showed peripheral and septal enhancement in 5 cases of conventional chondrosarcoma, showing variegated appearance in 3 cases and honeycomb-like appearance in 2 cases. Mesenchymal chondrosarcoma showed isointense signal on both T_1WI and T_2WI, with homogeneous and heterogeneous enhancement in one case, respectively. MRI showed the extent and the associated changes of the lesions more clearly compared to CT. Conclusion CT is the first modality of choice in the diagnosis of chondrosarcoma in sinonasal and orbital region. The typically peripheral and septal contrast enhancement can also suggest the diagnosis of chondrosarcoma on MRI. MRI can demonstrate optimally the invading extent and provide more accurate information for therapy as a complementary imaging method.