外周原始神经外胚叶肿瘤的临床及CT、MRI诊断

Peripheral Primitive Neuroectodermal Tumors: Clinical, CT and MRI Features

目的分析外周原始神经外胚叶肿瘤(pPNET)的临床特点和CT、MRI表现,以提高对该病的认识。资料与方法回顾分析8例经病理证实的pPNET的临床表现和CT、MRI征象。结果原发于上肢pPNET1例,头面部2例,腹膜后2例,脊柱旁3例。初诊时2例有骨转移,1例颌下淋巴结肿大。病灶体积较大,呈浸润生长,推压邻近结构,并可凸入椎管。肿瘤密度/信号不均,CT为软组织密度,轻至中度强化;MRT1WI肿块与肌肉等信号,T2WI呈不均匀高信号,增强扫描呈花环状或蜂窝状强化。1例有钙化,3例邻近骨质破坏,呈溶骨性破坏伴骨膜反应。结论pPNET是好发于青少年的少见恶性小圆形细胞肿瘤,预后差。CT、MRI征象无特异性,但对评价肿瘤的可切除性、治疗效果和制订治疗方案非常有价值。

Objective To describe the clinical, CT and MRI findings of peripheral primitive neuroectodermal tumors (pPNET). Materials and Methods Clinical, CT and MRI features in 8 cases with pPNET proved by pathological results were reviewed retrospectively.Results Primary sites were upper limbs (n=1), head (n=2), retroperitoneum (n=2), paraspinal (n=3). At the first time of diagnosis, 2 patients had bone metastases and 1 patient had subjaw lymph nodes enlargement. The tumors usually had big size with aggressive behavior , tended to displace adjacent soft tissue structures. The tumors were shown as density similar to soft tissue on CT and intermediate signal intensity on T_1-weighted images, hyperintensity on T_2-weighted. After gadolinium administration, annular and honeycomb enhancement was seen. 1 case had calcification in tumor. Local or bony invasion in bone marrow involvement with periosteal new bone formation were seen in 3 patients.Conclusion pPNET is a rare small round cell malignancies with poor prognosis commonly in children. Radiologic appearance is not specific, but MRI and CT are useful in predicting prognosis and resectable, in detecting distant metastases, and in the evaluation of response to treatment.