- Most common intramedullary neoplasm in children!
- 2nd most common intramedullary neoplasm in adults
Frequency: 30% of spinal cord tumors; 2nd in prevalence to ependymoma in adults
Mean age: 29 years; M÷F = 58÷42
Path: ill-defined fusiform cord enlargement without cleavage plane / capsule
Histo: hypercellularity with infiltrative growth along scaffold of normal astrocytes, oligodendrocytes and axons
- Grade I pilocytic astrocytoma (75%), usually most common in cerebellum
- Grade II low-grade fibrillary type
- Grade III anaplastic astrocytoma with necrosis (up to 25%)
- Grade IV glioblastoma multiforme with endothelial proliferation (0.2–1.5%)
Location: thoracic cord (67%), cervical cord (49%), conus medullaris (3%); on average over 4–7 vertebral segments involved; holocord presentation (in up to 60% in children); often extending into lower brainstem
Site: eccentric within spinal cord (57%)
- pain + sensory deficit (54%); torticollis (27%)
- motor dysfunction (41%), gait abnormalities (27%)
- eccentric irregular tumor cysts + polar cysts + syrinx (common):
- water-soluble myelographic contrast enters cystic space on delayed CT images
Radiographs:
- scoliosis (24%)
- widened interpedicular distance
- bone erosion
MR:
- usually extensive ill-defined homogeneous cord tumor with expansion of spinal cord:
- iso- to hypointense to cord on T1WI
- hyperintense on T2WI
- poorly defined margins
- dilated veins on surface of cord
- patchy irregular enhancement
- leptomeningeal spread (in 60% of glioblastoma multiforme)
Rx: tumor debulking + radiation therapy
Prognosis: 95% 5-year survival in low-grade tumors; higher mortality rate than for ependymoma
DDx: ependymoma (“cap” sign, central location, well defined, hemorrhage common, focal intense enhancement, predilection for conus)
◊Most common intramedullary spinal neoplasm in adults!
Frequency: 40–60% of primary spinal cord tumors; 90% of primary tumors in filum terminale
Mean age: 39 years; M÷F = 57÷43
Origin: ependymal cells lining the central canal (62–76%)
Path: symmetric cord expansion with displacement of neural tissue yielding a cleavage plane
Histo: perivascular pseudorosettes; cystic degeneration (50%); hemorrhage at superior + inferior tumor margins
- Subtypes: cellular (most common, cervical cord), myxopapillary (along filum terminale), papillary, clear cell, tanycytic, melanotic
Location: cervical cord alone (44%) / with extension into thoracic cord (23%); thoracic cord alone (26%); conus medullaris (7%); extends over several vertebral segments (on average 3.6 segments involved)
- ectopic: sacrococcygeal region, broad ligament of ovary (associated with spina bifida occulta [33%])
Site: central within spinal cord
- long antecedent history (mean duration of 37 months) ← slow tumor growth:
- back / neck pain (67%) = compression / interruption of central spinothalamic tracts first
- sensory deficits (52%), motor weakness (46%)
- bowel / bladder dysfunction (15%)
Metastases to: lung, retroperitoneum, lymph nodes
- well-demarcated / diffusely infiltrating cord tumor
- associated with at least one cyst (in 78–84%):
- polar cyst (62%) at cranial and caudal aspect of tumor, which do not contain malignant cells
- tumoral cyst (4–50%), which may contain tumor
- syringohydromyelia (9–50%)
Radiographs:
- scoliosis (16%)
- widening of spinal canal (11%):
- scalloping of vertebral body
- pedicle erosion, laminar thinning
Myelography:
- enlarged cord with complete / partial block to flow of contrast material
CT:
- iso- / slightly hyperattenuating cord mass
- intense enhancement
MR:
- iso- / hypointense (rarely hyperintense from hemorrhage) mass relative to spinal cord on T1WI
- hyper- / isointense on T2WI
- “cap” sign = extremely hypointense rim at the tumor poles on T2WI (in 20–33%) due to hemosiderin deposits from prior hemorrhage
- cord edema (60%)
- mostly intense homogeneous enhancement (84%) with well-defined margins (89%)
Prognosis: 82% 5-year survival rate
DDx: astrocytoma (pediatric tumor, eccentric location, ill defined, hemorrhage uncommon, patchy irregular enhancement)
Myxopapillary Ependymoma of Spinal Cord
= special variant of ependymoma of lower spinal cord
Prevalence: 13% of all spinal ependymomas; most common neoplasm of conus medullaris (83%)
Mean age: 35 years; M>F
Origin: ependymal glia of filum terminale
Path: heterogeneous tumor with generous mucin production
- lower back / leg / sacral pain
- weakness / sphincter dysfunction
Location: conus medullaris, filum terminale; occasionally multiple (14–43%)
- isointense on T1WI + hyperintense on T2WI
- occasionally hyperintense on T1WI + T2WI ← mucin content / hemorrhage
- almost always contrast enhancing
- occasionally large lytic area of bone destruction
Subependymoma of Spinal Cord
= variant of CNS ependymoma
Origin: tanycytes that bridge pial + ependymal layers[tanyos, Greek = stretch]
Mean age: 42 years; M÷F = 74÷26
Histo: sparsely dispersed ependymal cells among predominant fibrillar astrocytes
- 52 months mean duration of symptoms:
- pain, sensory + motor dysfunction
- atrophy of one / both distal upper extremities (83%)
Location: ventricular system of brain, some in cervical cord
- fusiform dilatation of spinal cord:
- enhancing lesion with well-defined borders (50%)
- nonenhancing lesion with diffuse symmetric cord enlargement
- eccentrically located mass
- ± edema
= GANGLIOGLIONEUROMA = GANGLIONIC NEUROMA = neuroastrocytoma = neuroganglioma = GANGLIONIC GLIOMA = = neuroglioma = NEUROMA GANGLIOCELLULARE
Prevalence: 0.4–6.2% of all CNS tumors; 1.1% of all spinal neoplasms
Mean age: 12 years; children >adults; M÷F = 1÷1
Histo: mixture of irregularly oriented neoplastic mature neuronal elements (neurons / ganglion cells) + glial elements (neoplastic astrocytes), arranged in clusters = grade I or II lesions
Location: cervical cord (48%), thoracic cord (22%), conus, holocord (average length of 8 vertebral segments); usually supratentorial (temporal lobe)
- duration of symptoms between 1 month and 5 years
- scoliosis (44%), spinal remodeling (93%) ← relatively slow growth (rare in astrocytoma / ependymoma)
- eccentric
- small tumoral cysts (in 46%)
- calcifications (rare compared with intracranial tumor)
MR:
- mixed tumor signal intensities on T1WI (in 84%)
- tumor homogeneously hyperintense on T2WI
- surrounding edema (less common than in ependymoma / astrocytoma)
- patchy (65%) / no (15%) tumor enhancement
- enhancement of pial surface (58%)
Cx: malignant transformation (10%)
Prognosis: slow growth; 89% 5-year and 83% 10-year survival rate ; 27% recurrence rate