不典型神经鞘瘤的影像学诊断

目的 探讨不典型神经鞘瘤的临床影像学表现特点。方法 回顾分析44例经病理学诊断的不典型神经鞘瘤的CT和MRI表现。结果 CT表现为类圆形或分叶状低密度或等低混杂密度灶,绝大多数（38/40）边界清楚,其中实性肿瘤17例,囊实性病灶19例,单纯囊性病灶4例。CT增强扫描肿瘤实质呈渐进性不均匀强化。囊性病灶内存在强化程度不一的结节灶可能是囊实性神经鞘瘤较为特征性的表现。实性病灶呈＂同心圆样＂强化可能是实性神经鞘瘤比较有价值的征象。MRI上肿瘤实质部分呈稍长T1稍长T2信号,囊性部分呈长T1长T2信号,病灶周围可见水肿信号;＂靶征＂是特征性的MRI表现。结论 不典型神经鞘瘤可发生在身体任何部位,熟悉其影像学特点对诊断很有帮助。

Imaging diagnosis of atypical schwannoma

Objective To explore clinical imaging characters of atypical schwannoma. Methods CT and MR imagings of 44 cases of atypical sehwannoma confirmed pathologically were retrospectively analysed. The lesions＇ site of the 44 cases distributed in head and neck in 18, thoracic in 10, abdomen in 10, and other parts in 6. 40 cases were performed plain CT scan and 24 out of those were performed enhanced scan. 10 cases were performed plain MR scan and 6 enhanced scan. Resuits CT demonstrated that lesions were round or lobular mass with low or low-isodensity. Most of the lesions （38/40） had distinct boundary. There were 17 solid lesions, 19 cystic-solid lesions and 4 cystic lesions. Parenchyma of the lesions presented gradual enhancement after contrast and varying degree of the enhanced nodes within a cystic lesion was characteristic for sehwannoma. Concentric circle like enhancement of solid lesions was a valuable sign of schwannoma. On MRI, the Parenchyma of schwannoma appeared slight long T1 and slight long T2 signal, the cystic parts of the lesions showed long T1 and long T2 signal. Edema could be found around the lesions and ＇target sign＇ was specific for diagnosis on MRI. Conclusion Atypical schwannoma can be found in any site of the body. Being familiar with the imaging characters is helpful for diagnosis.