CT在儿童外周性原始神经外胚层肿瘤诊断中的应用

Application of CT in pediatric peripheral primitive neuroectodermal tumors

目的:分析儿童外周性原始神经外胚层肿瘤(Peripheral primitive neuroectodermal tumor,pPNET)的CT表现,结合临床病理特征,以提高对该病的认识及临床诊断方法。方法:回顾性分析经病理证实的6例儿童(男∶女=2:4)pPNET的CT表现,6例均行CT平扫,其中4例又行增强检查。结果 :6例pPNET均为软组织肿物,2例位于胸壁,2例位于腹膜后,1例位于手掌背侧,1例位于骨盆。软组织pPNET多表现为较大的、边界不清的软组织肿物,伴或不伴邻近的骨质破坏。肿物内密度不均匀,伴有囊变、坏死及分隔,增强后多呈不均匀强化。6例患儿均行手术治疗,术中完整切除肿物,术后病理回报均考虑pPNET。结论:pPNET目前仍为少见病例,影像学表现缺乏特异性,确诊需要依靠病理组织检查及免疫组化,但CT检查在显示肿瘤的位置、大小、来源、血供情况以及邻近组织有否受累等具有较明确的提示。在儿童中,当CT检查提示巨大的、界限不清的软组织肿物包含囊变、坏死及分隔时,应高度怀疑pPNET。HE染色镜下可见Homer-Wright菊形团结构,免疫组化染色肿瘤均表达CD99,更能进一步提示pPNET。

Objective： To analyze the CT imaging and clinicopathologic features of the pediatric peripheral primitive neu- roeetodemal tumor （pPNET）. Methods： CT imaging of 6 cases with pathologically proven pPNET was retrospectively reviewed, among which 4 cases performed enhanced CT scan. Results： Of all cases, 6 lesions were located in the chest wall （n=2）, retroperitoneum（n=2）, palm dorsal（n=1）, and pelvis（n=1）. The pPNET in soft tissue appeared as a large, ill-defined mass, with （n=4） or without （n=2） bony invasion, and inhomogeneous density with cystic degeneration, necrosis and internal separations. Most tumors showed heterogeneous enhancement. All patients underwent surgical resection. Histopathological examinations were performed in all cases. Conclusion： Pediatric pPNET are rare with no typical imaging findings. CT is helpful in the display- ing location, size, source, blood supply and the involvement of neighbour tissues of tumors. The diagnosis of pPNET should he considered in young patients with a large, ill-defined, soft-tissue mass containing areas of cystic degeneration, necrosis and internal separations. The presence of Homer-Wright rosettes or immunohistochemical expression of CD99 supports the diagnosis of pPNET.