良性色素性外周神经源性肿瘤的影像学表现

目的探讨良性色素性外周神经源性肿瘤(BMPNT)的影像学特征。方法选取经手术病理证实7例色素性外周神经源性肿瘤患者行CT和MRI扫描,分析其特征。结果7例BMPNT均为单发,其中神经鞘瘤6例、神经纤维瘤1例;位于颈部3例,椎管内2例、鼻腔和后纵隔各1例。5例CT平扫表现为边界清楚不均匀软组织密度影,其内3例合并钙化,增强扫描呈轻中度强化。7例肿块在MRI平扫均表现为混杂信号影,其内含有不同范围短T1短T2信号区,其在瘤内呈结节状、斑片状或弥漫性分布,3例瘤内合并囊变坏死呈长T1长T2信号;增强扫描肿块呈轻度至明显不均匀强化。结论外周神经源性肿瘤含有黑色素是一种少见现象,其MRI表现具有一定特征。

The imaging features of benign melanotic peripherial neurogenic tumors

Objective To describe imaging features of the benign melanotic peripheral neurogenic tumors(BMPNT),and to improve the ability for the diagnosis and decrease in misdiagnosis.Methods The imaging materials of 7 patients with BMPNT confirmed pathologically were reviewed.Among them,5 cases underwent unenhanced CT scanning,3 of them were performed by enhanced CT scanning;7 cases were performed by unenhanced MRI scanning,5 of them by enhanced MRI scanning.Results All of 7 cases with BMPNT were singular,including 6 schwannomas and 1neurofibroma;of them,3 were located in the neck,2 in spinal canal,1 each in the nasal cavity and in the posterior mediastinum.On unenhanced CT images,5 masses presented well-defined,heterogenous,soft-tissue density,in which calcifications were found in 3 cases;they were slightly or moderately enhanced on enhanced CT scanning.On enhanced MRI images,all of 7 cases were heterogeneously,slightly to markedly enhanced.The nodular,patchy or diffusive short-T1 and short-T2-signal areas were found in the masses,3 of them presonted with intratumoral cystic and necrotic areas depicting short-T1-and long-T2 signal;5 masses were mildly to markedly,heterogenously enhanced on enhanced MRI scanning.Conclusion Melanin rarely occurs in the peripherial neurogenic tumors,and its MRI appearance has some characteristic.MRI combining with the predilection location is helpful to improve the diagnosis of BMPNT.