原始神经外胚层肿瘤的影像学特征

The imaging features of primitive neuroectodermal tumor

目的 探讨原始神经外胚层肿瘤（PNET）的影像学征象。方法 回顾性分析经手术病理证实的影像（MRI/CT）资料齐全的21例PNET,分析其病理特点,结合文献资料,探讨PNET的影像学（MRI/CT）特征,以提高对该病的认识。结果 PNET多见于青少年,中位发病年龄为21岁,男性13例,女性8例,20例单发病灶,1例多发病灶,其中颅内2例,颈部1例,胸腔2例,肋骨1例,腋窝1例,腹腔1例,腹膜后1例,盆腔1例,肾脏2例,椎管4例,四肢5例,均可见软组织肿块,直径3.2～20.0cm,平均10.4cm,肿块呈不规则形或类球形,13例边缘清晰,与周围结构分界清,19例肿块内密度/信号不均,见囊性坏死区,均未见明显钙化或肿瘤骨,7例见溶骨性骨质破坏,破坏区形态不规则,骨皮质连续性中断,未见明显硬化边缘,未见明显骨膜反应,增强扫描肿瘤实性成分明显不均匀强化,坏死区无明显强化。结论 PNET可发生于全身任何部位,MRI/CT可准确显示肿瘤的位置、大小、形态、边缘及与周边组织的关系,影像表现具有一定特征性,但并无特异性,诊断依靠病理组织检查。

Objective To explore the imaging features of primitive neuroect0dermal tumor （PNET）. Methods The MR/CT imaging of 21 patients with PNET pathologically proved were reviewed retrospectively. The imaging features and pathological characteristics were analyzed. Results PNET was more commonly occurred on young people, the median age was 21 years, including 13 males and 8 females. Among 21 patients with PNET, solitary lesion was found in 20 patients, and 1 patient showed muhiple lesions which were both located on bone. Sites of lesions involvement were 2 cases in head, 1 case in neck, 2 cases in chest, 1 case. in rib, 1 case in axillary, 1 case in abdominal, 1 case in retroperitoneal, 1 case in pelvis, 2 cases in renal, 4 cases in spinal canal, and 5 cases in extremities. All the cases showed soft tissue mass, tumor size ranged from 3.2 cm to 20.0 cm （ average （ 10.4 ±7.1 ） cm. The lesions were irregular or spherical, 13 cases with clear circumscribed, 19 cases with inhomogeneous cystic low density/signal intensity within tumors. No obvious calcification or osteoid tissues were found within the lesions. 7 cases showed irregular osteolytic lesion and cortical discontinuous in bone, without peristeal reaction or hardened edge. All of the lesions Were heterogeneous enhancement on CT/MR. Conclusion PNET can occur in any part of the body. CT/MRI can accurately show the location, size, shape and edge of the tumor, the relationship with surrounding tissue. Certain CT/MR findings may suggest the diagnosis of PNET, but still rely on pathological diagnosis.