外周原始神经外胚层肿瘤的CT诊断

CT appearance of peripheral primitive neuroectodermal tumors

目的分析外周原始神经外胚层肿瘤(pPNET)的CT表现,提高对该病的认识。材料与方法回顾性分析12例经病理诊断的外周原始神经外胚层肿瘤的CT表现。结果9例表现为溶骨性骨质破坏,伴有软组织肿块;3例为混合性骨质破坏与软组织肿块,除2例发生在胸椎和1例发生在髋臼的病灶较小外,其余病灶都较大,最大平均直径为10cm。其中6例可见细小骨膜反应。软组织肿块低于邻近正常肌肉密度,多以替代和(或)推移邻近结构方式生长。2例软组织肿块中可见散在小点状钙化。1例可见邻近淋巴结转移。结论pPNET的CT表现为非特异性,典型表现为溶骨性骨质破坏和较大软组织肿块,肿瘤以替代邻近结构方式生长,肿瘤钙化与邻近淋巴结转移少见。CT能较好显示病变内部结构,明确病变范围及与邻近结构关系,有助于术前分期、手术方案的确定、有无远处转移和治疗效果评价。

Objective: To present the CT features and improve the knowledge of peripheral primitive neuroectodermal tumors(pPNETs). Materials and Methods: The CT appearances of 12 patients with pPNETs pathologically proved were analyzed retrospectively. Results: Age range at diagnosis was 9～68 years(mean 21.6 years)old. Sites of tumor: scapula(n=1), sacrum(n=1), ileum(n=3), vertebra(n=2), acetabulum(n=1), proximal side of humerus(n=3), distal side of femur(n=1). CT findings of 9 bone pPNETs were soft mass of homogeneous or heterogeneous density and osteolytic destruction without osteosclerosis, one of which was osteolytic destruction with circumference sclerosis, 2 cases were mixed bone destruction with soft mass. 1 case was of both bulging osteolytic destruction and expanding tumor bone formation. Six cases have small periosteum reaction. Tumors tended to displace adjacent soft tissue structures rather than invade or encase them. Calcification was uncommon(n=2), regional lymphadenopathy and presumed tumor involvement was rare(n=1). Conclusion: The CT features of pPNETs are non-specific. Performing tissue diagnosis is essential. However, CT can show the intra-tumor structures and the extent of the tumor very well, which is helpful in differentiating diagnosis, predicting resectability, detecting distant metastasis and evaluating the response to treatment.