[CT and MRI features of peripheral primitive neuroectodermal tumor].

BACKGROUND & OBJECTIVE: It's difficult to distinguish peripheral primitive neuroectodermal tumor (PNET) from other small round cell tumors such as Ewing's sarcoma by histological examination. This study was to analyze the CT and MRI features of peripheral PNET.

METHODS: The CT and MRI records of 7 patients with pathologically proved peripheral PNET were reviewed.

RESULTS: The tumors were located in the left ala nasi, right lower jaw bone, left chest wall, right chest wall, left spermatic cord, paraspinal, and lumbar vertebral canal. The tumors in soft tissue showed resembled non-calcified, ill-defined soft tissue masses with cystic or necrotic areas on CT images, with heterogeneous enhancement on contrast images. The tumors in the bone showed lytic lesions with large soft tissue masses on CT images. The tumors in the paraspinal and vertebral canal showed well-defined soft tissue masses without involving cord and cauda equine on MRI, and showed isointensity or hypointensity on T1WI and isointensity or hyperintensity on T2WI.

CONCLUSIONS: The imaging features of peripheral PNET are non-specific. CT and MRI are useful in delineating the extent, finding distant metastasis, predicting respectability and monitoring treatment of peripheral PNET.