【病例】颈部迷走神经鞘瘤1例CT及MR影像表现

14 8月

57-year-old male with right sided swelling of the submandibular gland.

57岁男性右下颌下腺肿胀。

【病例】颈部迷走神经鞘瘤1例CT及MR影像表现

【病例】颈部迷走神经鞘瘤1例CT及MR影像表现

【病例】颈部迷走神经鞘瘤1例CT及MR影像表现

【病例】颈部迷走神经鞘瘤1例CT及MR影像表现

【病例】颈部迷走神经鞘瘤1例CT及MR影像表现

【病例】颈部迷走神经鞘瘤1例CT及MR影像表现

【病例】颈部迷走神经鞘瘤1例CT及MR影像表现

 Vagal Schwannoma 

迷走神经鞘瘤

Vagal schwannomas are benign tumors that may present with hoarseness or cough, however the majority of patients are asymptomatic.

Schwannomas of the vagus nerve need to be differentiated from paragangliomas because the distinction may influence treatment planning

迷走神经鞘瘤是良性肿瘤,可伴有声音嘶哑或咳嗽,但大多数患者无症状。

迷走神经的神经鞘瘤需要与副神经节瘤区别开来,因为这种区别可能会影响治疗计划。

Schwannomas are benign neoplasms which arise from the nerve sheath and consist of schwann cells in a collagenous matrix. Histologically, the terms Antoni type A and Antoni type B are used to describe varying growth patterns. Type A tissue has elongated spindle cells and is compact in nature while type B has a looser organization with cystic spaces intermixed within the tissue. These cystic spaces result in high signal intensity on T2 weighted MR sequences.

神经鞘瘤是一种良性肿瘤,起源于神经鞘膜,其由雪旺细胞包含在胶原基质中所组成。

在组织学上,术语Antoni A型(肿瘤细胞区)和Antoni B型(粘液基质区)用于描述不同的生长模式。

A区组织具有伸长的梭形细胞并且结构紧凑,而B型具有较松散的组织,其中囊变区混合在其内, 这些囊变区在T2WI上呈高信号。

Vestibular schwannomas are the most common cranial nerve (CN) schwannoma, followed by trigeminal and facial and then glossopharyngeal and vagus schwannomas. CN schwannomas are usually isolated lesions, except when they are associated with neurofibromatosis type 2 (NF2). NF2 is characterized by bilateral acoustic schwannomas but other CN schwannomas also occur at an increased frequency in these patients.

前庭神经鞘瘤是最常见的中枢神经神经鞘瘤,其次是三叉神经和面神经,再其次是舌咽、迷走神经神经鞘瘤。中枢神经鞘瘤通常是孤立的病变,除了当它们与神经纤维瘤病2型(NF2)相关。NF2的特点是双侧听神经鞘瘤,但其他中枢神经鞘瘤发生在这些患者的频率也增加。

The majority of carotid space masses are benign, with the two most common lesions being the vagus schwannoma and the glomus tumor. Neoplasms of the vagus nerve include paragangliomas (50%), schwannomas (31%), neurofibromas (14%), and neurofibrosarcomas (6%). Most cases of schwannomas manifest between the third and sixth decades of life as a firm and painless mass in the neck.

大多数颈动脉间隙肿块是良性的,其中最常见的两种病变是迷走神经鞘瘤和血管球瘤。迷走神经肿瘤包括副神经节瘤(50%)、神经鞘瘤(31%)、神经纤维瘤(14%)和神经纤维肉瘤6%)。大部分神经鞘瘤发生于30至60岁之间,表现为颈部固定的无痛性肿块。

Schwannomas of the vagus nerve are usually well-defined, rounded structures which are hypodense to muscle on CT and enhance moderately. On MR, there is variable T2 signal intensity depending on its content of Antoni A and Antoni B tissue. Hemorrhageand cystic degeneration are not uncommon. They result in anterior displacement of the carotids. In contrast, paraganglioma are highly vascular and demonstrate dramatic enhancement. Flow voids are usually visualized, resulting in the characteristic salt-and-pepper appearance. Carotid body tumors tend to splay the internal and external carotid arteries away from each other, while glomus vagale tumors displace the carotid artery anteriorly. The distinction between avagus schwannoma and the glomus vagale tumor has to be made on the basis of flow voids and vascular flow curves. Also, glomus vagale tumors are relatively uncommon.

迷走神经鞘瘤通常边界清楚,呈类圆形,在CT上与肌肉呈低密度并中度强化。在MR上,根据A区和B区成分的多少不同而表现为不同的T2信号强度。出血和囊性退变并不少见。肿瘤可导致颈动脉前移。

相反,副神经节瘤富血供,明显强化。可见血管流空,导致特征的盐和胡椒样表现。颈动脉体瘤倾向于使颈内、外颈动脉彼此远离,而迷走神经肿瘤则导致颈动脉前移。神经鞘瘤和血管球瘤之间的区别主要基于血管流空及血流曲线。此外,颈动脉体瘤相对少见。

图像解析

【病例】颈部迷走神经鞘瘤1例CT及MR影像表现

【病例】颈部迷走神经鞘瘤1例CT及MR影像表现

【病例】颈部迷走神经鞘瘤1例CT及MR影像表现

Contrast enhanced axial CT images through the neck demonstrate a 4.5X6cm circumscribed and moderately enhancing mass within the right carotid space with scattered areas of low density centrally within the mass (blue arrows). The internal and external carotid arteries (green arrows) as well as the parapharyngeal fat (red arrow) are displaced anteriorly. The parotid gland is separate from the lesion (purple arrow).

轴位增强CT示颈部右侧颈动脉鞘区见一4.5×6cm肿物,边界清楚,中度强化,瘤内可见片状低密度区(蓝箭)。颈内、外动脉(绿箭)以及咽旁脂肪(红箭)向前移位。腮腺(紫箭)与病变分界清楚。

【病例】颈部迷走神经鞘瘤1例CT及MR影像表现

【病例】颈部迷走神经鞘瘤1例CT及MR影像表现

【病例】颈部迷走神经鞘瘤1例CT及MR影像表现

【病例】颈部迷走神经鞘瘤1例CT及MR影像表现

Axial and coronal T2 weighted images and axial and coronal T1 weighted post-gadolinium fat saturated images again show a well defined mass with heterogeneous T2 signal and areas of cystic degeneration (blue arrows). There is peripheral enhancement following gadolinium administration (orange arrows). Note that the mass is not contiguous with the parotid gland (purple arrows).

轴位及冠状T2WI、轴位及冠状T1WI增强压脂图像示肿物边界清楚,T2信号不均,可见囊变区(蓝箭),增强后外周明显强化(橙箭)。肿物与腮腺(紫箭)没有联系。

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