Abstract：Objective: To explore the pathology and X-ray, CT and MR images of peripheral primitive neuroectodermal tumors(PPNET) as well as correlate with pathologic results, to improve the diagnostic accuracy of peripheral primitive neuroectodermal tumors. Materials and Methods: X-ray, CT and MRI findings in 10 patients with PPNET were retrospectively analyzed, then correlated with pathology. Results: In the ten lesions 3 were located in the tibia, 1 in humerus, 2 in chest wall, 2 in pelvic bone, 1 in inguinal region, 1 in retroperitoneum. The X-ray findings of 4 cases were lytic bone destruction, lytic lesion with irregular sclerosis and expansion(1 case). The CT findings included irregular lytic lesion(4 cases), lytic lesion with rim-like sclerosis and expansion(1 case). Five tumors in soft tissue showed ill-defined, irregular and heterogenous cystic areas. The tumors showed moderate heterogeneous enhancement after injection of contrast agents. The 10 cases in bone and soft tissue MRI findings showed iso- or hyperintensity on T1WI, and heterogeneous hyperintensity on T2WI. The tumors showed heterogeneous enhancement and reticular enhancement after injection of contrast agents. Homer-Wright daisy-group was a specific pathologic feature of PPNETs. According to immunohistochemical results, all tumor cells showed positive for CD99, and showed various degrees of antigen in epithelium, including NSE, Syn, S-100 and Vimentin. Conclusion: If X-ray, CT and MRI can be used reasonably, the accuracy of diagnosis of PPNET can be improved, the definite diagnosis is depended on the pathological and immunohistochemical results.
2012, Vol. 23 
