原始神经外胚层肿瘤的CT、MR诊断

CT and MRI Diagnosis of Primitive Neuroectodermal Tumor

目的分析原始神经外胚层肿瘤(PNET)的CT与MRI表现,以提高对本病的认识。方法回顾性分析经病理证实的17例PNET的CT和MRI表现,其中中枢性原始神经外胚层肿瘤(cPNET)4例,外周性原始神经外胚层肿瘤(pPNET)13例,男11例、女6例。13例行CT检查,其中8例行CT平扫加增强检查,1例行CT增强检查;8例行MRI检查,其中7例行平扫加增强,1例行MRI平扫。结果 4例cPNET位于脑内及鞍区,3例表现为较大肿块,边界清晰,密度(或信号)不均匀,呈稍高密度(或稍长或等T1、长T2信号),周围伴有轻-中度水肿,1例伴出血,4例均无钙化,增强扫描实性部分明显不均匀强化。13例pPNET中,4例位于胸壁,3例累及骨骼,腹壁、肩部、椎管、下肢软组织、鼻窦及肾上腺各1例。软组织pPNET多表现为较大的、边界不清的软组织肿块,密度(或信号)不均匀,伴坏死、囊变,不伴钙化,增强后多呈不均匀强化;骨pPNET主要表现为较大的溶骨性骨质破坏伴软组织肿块,未见骨膜反应及钙化,1例在MRI上表现为稍长T1、长T2信号。结论 PNET的CT与MRI表现缺乏特征性,但在显示肿瘤的内部结构、明确肿瘤的范围等方面有其重要价值。

Objective To improve the recognition of primitive neuroectodermal tumor（PNET） by analyzing CT and MR appearances. Methods A retrospective review of CT and MR findings of 17 cases with PNET pathologically proven was performed, 4 cases were central primitive neuroectodermal tumor （cPNET） and 13 cases were peripheral primitive neuroectodermal tumor （pPNET）. 11 cases were men, 6 cases were women, 13 cases carried out CT scan, among which 8 cases performed plain and enhanced CT scan, 1 ease performed enhanced CT scan. 8 cases performed MRI scan, among which 7 cases performed plain and enhanced scan, 1 case with plain scan. Results Of the 17 eases with PNET,4 cases located at intracerebral and sellar region ,3 lesions appeared as large, well defined and manifested as heterogeneous density （or signal ） , slightly hyperdense （or iso hypointensity on T_1 WI, hyperintensity on T_2WI） , slight peritumoral edema, hemorrhage in one case and none calcification in 4 cases. The tumors demonstrated heterogeneous contrast enhancement. 13 cases of pPNET located in chest wall （4） , bone （3） , abdomen wall, shoulder, spinal canal, paranasal sinuses, adrenal gland in one case respectively, pPNET in soft tissue appeared as a large, ill defined mass, and heterogeneous density（ or signal） with necrosis, cystic without calcification, most tumors presented as heterogeneous contrast enhancement; pPNET arising from bone demonstrated extensive lytie lesion with large soft tissue mass without periosteum reaction and calcification. One lesion showed slightly hypointense on T_1WI, hyperintensity on T_2WI. Conclusion CT and MR appearances of PNET are not specific,however CT and MR images have important value in depicting the intratumor structures, the extent of the tumor.