MRI and pathological features of peripheral primitive neuroectodermal tumors:Analysis of 7 cases / 中国医学影像技术

ABSTRACT

Objective To analyze MRI features of peripheral primitive neuroectodermal tumor (pPNET) in comparison with pathological findings. Methods The clinical manifestation, pathological features and the MRI appearances of 7 patients with pathologically proved pPNET were analyzed retrospectively. Results Among 7 patients, 2 patients located in intracalvarium, 2 in lower extremities, 1 in vertebral canal and extended outside of vertebral canal, 1 in cavitas pelvis and involved sacrum, and the rest 1 in the retroperitoneal space. The lesions in soft tissue manifested as iso-intensity on T1WI, slight hyper-intensity on T2WI with cystic degeneration and hemorrhage. Pseudo-capsule was seen in 1 patient. The solid parts of pPNET enhanced markedly after the contrast agent was injected. The adjacent bones were usually involved. pPNET in bone presented as osteolytic destruction of bone with large soft tissue mass. Immunohistochemical examination showed CD99 expression in all 7 patients, synaptophysin (Syn) expression in 4, Chromogranin (CgA) expression in 3, neuron specific enolase (NSE) expression in 2, vimentin (Vim) expression in 2 and EMA in 1 patient. Conclusion MRI has important reference value in diagnosis of pPNET, but final diagnosis still depends on the pathological and immunohistochemical examination.