Ewing's tumor of sacrum is rare, but should be suspected in low backache in children. MRI can identify cases early and enables early treatment though it is not specific.

From the manuscript

Sacral Ewing`s Sarcoma and Challenges in it`s Diagnosis on MRI

Abstract
A 15-yr old boy presented with low backache for 4 months associated with weakness of left lower limb. MRI of lumbosacral spine showed a sacral lesion with intraspinal and presacral soft tissue extension with neural compression. A diagnosis of tuberculosis was considered in the view of high prevalence in this part of the world, however biopsy revealed Ewing`s sarcoma. Ewing`s tumor of sacrum is rare, but should be suspected in low backache in children. Differential diagnosis for a sacral lesion includes tuberculosis, pyogenic osteomyelitis, lymphoma, chordoma, osteosarcoma and Ewing`s sarcoma. MRI is sensitive in detecting these lesions but is nonspecific requiring histopathological examination for confirmation.