肝门部胆管神经鞘瘤的影像学表现

Imaging Features of Biliary Tract Schwannoma in the Porta Hepatis

目的分析肝门部胆管神经鞘瘤的临床及病理资料,探讨原发于肝门部胆管神经鞘瘤的CT及MRI表现,提高对该病的认识和诊断水平。资料与方法回顾性分析8例经手术病理证实的肝门部胆管神经鞘瘤的影像学资料,5例行CT检查,3例行MRI检查,观察病灶数目、部位、大小、形态、边缘、密度、信号、强化模式等,并与病理结果进行对照。结果 7例为单发病灶,1例有2个病灶,共9个病灶;8个病灶为囊实性肿块,1个为实性肿块。5例CT平扫表现为肝门区及其上方、胰颈部上方见类圆形、椭圆形等或稍低密度肿块,边界清晰,其内可见低密度囊性区;3例行MRI扫描,病灶实性部分T1WI表现为稍低或等信号,T2WI为等信号或稍高信号。增强扫描表现为进行性或不均匀延迟强化,坏死囊变区不强化。CT及MRI均可以清晰显示病灶周围有完整的包膜,边界清晰;肿瘤紧邻或推压周围血管及胆管,未见包裹侵犯。3例合并胆总管或肝内胆管轻度扩张。病理以肿块有完整的纤维包膜、瘤细胞呈梭形为主要特征。结论肝门部胆管神经鞘瘤具有特征性的影像学表现,具有良好的定位诊断价值,可以为诊断提供依据。

Purpose To improve the recognition and diagnosis of biliary tract schwannoma in the porta hepatis by analyzing patient＇s pathology and investigating the CT and MRI features. Materials and Methods In eight patients with pathology proven bile duct schwannoma in the porta hepatis, the imaging features and clinical information were retrospectively reviewed including five patients with CT and three patients with MRI. The number of lesions, location, size, shape, margin, density （or signal intensity on MRI）, and the enhancement pattern were analyzed and compared with pathology. Results There were a total of nine tumors including seven patients with solitary lesion and one patient with two lesions. Eight lesions were solid with cystic component; one lesion was solid. In five patients undergoing CT, the tumors were isoor hypo-attenuation, well-defined mass with low attenuation cystic component located in the porta hepatis, above the porta hepatis region or at the pancreatic neck （four patients）. In the other three patients, the MRI showed low, or iso-intensity on T1WI and high or iso-intensity on T2WI. Progressive or heterogeneous delayed enhancement was demonstrated following contrast enhancement （four patients with CT and one patient with MRI respectively）. The cystic component was not enhanced. The tumors were encapsulated and well-circumscribed, abutting or displaying the adjacent blood vessels and bile ducts. Mildly dilated intrahepatic bile duct or common bile duct was found in three patients, Main pathology features included fusiform neoplastic cells and complete encapsulation. Conclusion Bile duct schwannoma in the porta hepatis has characteristic CT and MRI findings to help with the diagnosis.