Purpose: Primary spinal extradural Ewing's sarcoma (PSEES) or primitive neuroectodermal tumor (PNET) is uncommon. The present study summarizes the magnetic resonance (MR) imaging appearance of PSEES.
Methods: Literature search from 1994 to 2012 with our representative case presentation.
Results: Twenty-one patients, 12 males and 9 females, aged 3 weeks to 44 years, were identified. The thoracic spine was most frequently affected, followed by the cervical, cervicothoracic, and thoracolumbar spine. Superior-inferior extension of lesions was three vertebral levels in 7, two in 7, five in 4, four in 1, one in 1 and unknown in 1. PSEESs appeared isointense in 9 cases, hypointense in 2, hyperintense in 1, and no description in 9 on T1-weighted imaging, while hyperintense in 6, hypointense in 3, heterogeneous in 1, and no description in 11 on T2-weighted imaging. Varying enhancement was noted in 13 cases (62 %), with no description of contrast study in the other 8 cases. Dumbbell-shaped configuration of PSEES was found in 5 cases, foraminal widening in 4, and erosions or scalloping of the adjacent vertebral bodies in 4.
Conclusion: The MR imaging appearance of PSEESs is indistinguishable from other tumors. PSEES should be assumed as the differential diagnosis of spinal extradural tumors in pediatric, adolescent, and young adult patients, and prompt surgical exploration should be performed.