Table 2.

Radiological characteristics of the sacral tumors:^4,8

Characteristics	Schwannoma	Neurofibroma	Chordoma
Behavior	Benign	Benign	Malignant
Origin	Schwann cells	Schwann cells	Notochord remnants
Extension	No extension to neighboring tissues, mass eccentric to the nerve	Mass central to the nerve with no extension to neighboring tissues	Large expanding and destructive osteolytic lesion
Radiological characteristics	Hypo or isointense on T1, hyperintense and heterogenous on T2, target sign^ and fascicular sign a	Hypointense on T1, hyperintense on T2, target sign and fascicular sign	Peripheral amorphous calcifications inside the vertebral body Low-to-intermediate MRI signal on T1 sequences, hyperintensity on T2

^Target sign: Low or intermediate central signal on T2 due to fibrous tissue, with hyperintense peripheral signal on T2 due to myxoid tissue. ⁴

^aFascicular sign: Ring-shaped structures corresponding to fascicular bundles, visualized in the cross section of normal nerves. ⁴