Peripheral enhancing (faint) or nonenhancing (more common) loculated extramedullary CSF intensity fluid collection

Displaces adjacent spinal cord or nerve roots

CSF signal intensity on T1WI MR, ≥ CSF signal on T2WI MR

Consider FLAIR MR to accentuate signal differences between cyst and CSF (analogous to imaging brain arachnoid cyst)

Peripheral nervous system nerve sheath neoplasm originating from Schwann cells

Typically originates from dorsal rather than ventral spinal nerve roots

Arises from single nerve fascicle and displaces other adjacent nerve fascicles peripherally

Slow growing, benign tumor originating from dura mater

Presence of diffuse or focal intraspinal calcification helps suggest a specific diagnosis

Calcified portions may be hypointense on both T1WI MR and T2WI MR or be relatively inconspicuous

Intraspinal cyst lined with enteric mucosa

Abdominal or mediastinal location

Look for associated vertebral abnormalities (persistent canal of Kovalevsky, segmentation, and fusion anomalies) to help make diagnosis

However, not all neurenteric cysts are associated with vertebral segmentation anomalies however

Infection of spinal cord leptomeninges and subarachnoid space cerebrospinal fluid surrounding spinal cord

Best diagnostic clue is diffuse, extensive subarachnoid enhancement of meninges and identification of CSF inflammatory loculations

Additional helpful clues (when present) include “dirty” CSF showing slightly increased T1 & T2 signal intensity or presence of fluid/debris level in terminal thecal sac

CNS parasitic infection caused by pork tapeworm (Taenia solium)

Thoracic (60-75%) > cervical, lumbar location

May be extraspinal (vertebral body) or intraspinal (extradural, subarachnoid, intramedullary)

Most frequently see multilocular cysts rather than a single cyst

Post-inflammatory adhesions producing clumping of nerve roots

Best diagnostic clue: Nonidentification of discrete nerve roots within thecal sac (“empty sac sign”)

Evidence of prior lumbar surgery or residual intrathecal Pantopaque myelographic contrast helps suggest correct diagnosis

Intradural ossification associated with post-inflammatory adhesions and clumping of lumbar nerve roots

Evidence of prior lumbar surgery or residual intrathecal Pantopaque myelographic contrast helps suggest correct diagnosis

Look for focal calcific density on CT or hyperintensity on T1WI and T2WI within lumbar nerve root aggregate

Disease caused by cyst stage of echinococcus genus tapeworm infestation

Usually seen in patients living in endemic area for echinococcus

Liver, lung involvement are most common

Bone involvement is rare

Best diagnostic clue: Identification of multiloculated, multiseptated T2 hyperintense vertebral body/posterior element mass showing minimal enhancement

Hereditary disorder characterized by focal or diffuse peripheral nerve enlargement

Fusiform peripheral nerve mass(es) ± cauda equina nerve roots