CT和MRI诊断鼻及副鼻窦外周型原始神经外胚层肿瘤

目的 探讨鼻及副鼻窦外周型原始神经外胚层肿瘤（pPNETs）的CT和MRI表现。方法 回顾性分析7例经病理证实的鼻及副鼻窦pPNETs的影像学资料。4例同时接受CT、MR平扫及增强检查，2例仅接受CT平扫检查，1例仅接受MR增强检查。结果 CT平扫病灶为等肌肉密度的软组织肿块，MR SE T1WI为等信号，T2WI为略高信号，可见囊变或坏死（n=2）、出血（n=2），增强扫描明显不均匀强化。病灶广泛累及周围结构，周围骨质筛孔状破坏，轻度膨胀并可见残存骨壳。结论 鼻腔及副鼻窦pPNETs的密度、信号无明显特征性。病变所致的骨质改变可能对其鉴别诊断有一定意义。CT可较好地显示骨质破坏的情况，MRI可较好地显示肿瘤的内部结构及侵犯范围。

CT and MRI findings of peripheral primitive neuroectodermal tumors of nasal cavity and paranasal sinuses

Objective To analyze CT and MRI characteristics of nasal cavity and paranasal sinuses peripheral primitive neuroectodermal tumors (pPNETs). Methods The CT, MRI findings of 7 patients with pPNETs in nasal cavity and paranasal sinuses confirmed by pathology were analyzed retrospectively. Four cases undwerwent CT, MRI and enhanced scanning, 2 cases underwent CT scan and 1 cae underwent MR enhanced scanning. Results All the lesions demonstrated isodensity masses compared to muscle on CT plain scan, which were isointense than muscle on T1WI and mildly hyperintense and heterogeneous on T2WI. Some had cystics or necrotic areas (n=2), or haemorrhage (n=2). Marked heterogeneous enhancement with intravenous contrast agents was observed on CT or MRI. All of the lesions encroached the surrounding structures. The surrounding bones were cribriform destructed, and mild swelled, and the remaining bony shell were found. Conclusion The imaging features of pPNETs of the nasal cavity and paranasal sinuses are non-specific. A series of bone changes caused by lesions maybe have certain significance for diagnosis and differential diagnosis. CT can show the destruction of bone better, and MRI can reveal more details in structure and scope of the tumor.