CT Features Analysis of Peripheral Primitive Neuroectodermal Tumor

Objective: To investigate the CT manifestations of peripheral primitive neuroectodermal tumor(pPNET) in order to improve the diagnostic ability of the disease. Methods: CT images of 14 pPNET confirmed by pathology were analyzed retrospectively, and the imaging features were summarized, including location, size, shape, density, enhancement mode, boundary and metastasis. Results: 6 females and 8 males patients were included. The median age was 34 years. Among the 14 pPNET, 4 cases occurred in the abdominal cavity, 3 cases in the retroperitoneum, 3 cases in the pelvis, 2 cases in the posterior mediastinum, 1 case in the rib, and 1 case in the pelvis. 8 cases were single mass, 6 cases were multiple mass or nodule. In 12 cases(85.71%), the diameter of lesions was more than or equal to 5 cm. The single lesion usually showed irregular lobulation. On nonenhanced CT scan, the density was not uniform, low density necrosis area was found in the focus, and spot calcification was found in 4 cases. The average CT attenuation of solid part of the lesions was about 41.18 HU, and the enhanced lesions showed light to medium enhancement. The average CT value of arterial phase, portal phase and delayed phase increased by 14.85 HU, 21.42 HU and 22.50 HU, respectively. Multiple lesions appear as nodule or mass of varying sizes. The density, borders, and enhancement characteristics of multiple lesions was similar to single lesion. There were 2 cases with peripheral venous thrombosis. Among the 12 cases, 7 had lymph node metastasis. Peritoneal metastasis was found in 3 patients. Conclusion: The CT manifestations of pPNET have some features. Enhanced CT can clearly show the extent of lesions, surrounding invasion and metastasis and provide important diagnostic information for clinical work.