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Differential Diagnosis of Skull and Spine Disorders

Intramedullary Lesion!!navigator!!

Prevalence: 4–10% of all CNS tumors; 20% of all intraspinal tumors in adults (35% in children)

  1. TUMOR
    • expansion of cord
    • heterogeneous signal on T2WI
    • cysts + necrosis
    • variable degrees of enhancement (vast majority with some enhancement)
    1. primary:
      1. Ependymoma 60%
        • Most common glial tumor in adults
      2. Astrocytoma 25%
        • Most common intramedullary tumor in children
      3. Hemangioblastoma 5%
      4. Oligodendroglioma 3%
      5. Epidermoid, dermoid, teratoma 1–2%
      6. Ganglioglioma 1%
      7. Lipoma 1%
        location:
        • cervical region: astrocytoma
        • thoracic region: teratoma-dermoid, astrocytoma
        • lumbar region: ependymoma, dermoid
    2. metastatic: eg, malignant melanoma, breast, lung
  2. CYSTIC LESION
    • fluid isointense to CSF
    • smooth well-defined internal margins
    • thinned adjacent parenchyma
    • cord atrophy
    • no contrast enhancement
    1. peritumoral cyst = syringomyelia
      1. Syringomyelia
      2. Hydromyelia
      3. Reactive cyst
    2. tumoral cyst
      • shows peripheral enhancement
      1. Ganglioglioma (in 46%)
      2. Astrocytoma (in 20%)
      3. Ependymoma (in 3%)
      4. Hemangioblastoma (2–4%)
  3. VASCULAR
    1. Cord concussion = reversible local edema
    2. Hemorrhagic contusion
    3. Cord transection
    4. AVM
  4. CHRONIC INFLAMMATION
    1. Sarcoid
    2. Transverse myelitis
    3. Multiple sclerosis

mnemonic: I'M ASHAMED

  • Inflammation (multiple sclerosis, sarcoidosis, myelitis)
  • Medulloblastoma
  • Astrocytoma
  • Syringomyelia / hydromyelia
  • Hematoma, Hemangioblastoma
  • Arteriovenous malformation
  • Metastasis
  • Ependymoma
  • Dermoid

Intramedullary Neoplastic Lesion

  1. GLIAL NEOPLASM (90–95%)
    1. Ependymoma 60%
    2. Astrocytoma 33%
    3. Ganglioglioma 1%
  2. NONGLIAL NEOPLASM
    1. highly vascular lesions
      1. Hemangioblastoma
      2. Paraganglioma
    2. rare lesions
      1. Metastasis
      2. Lymphoma
      3. Primitive neuroectodermal tumor
  3. USUALLY EXTRAMEDULLARY NEOPLASM
    1. Intramedullary meningioma
    2. Intramedullary schwannoma

Intramedullary Nonneoplastic Mass

  1. Epidermoid
  2. Congenital lipoma
  3. Posttraumatic pseudocyst
  4. Wegener granuloma
  5. Cavernous malformation
  6. Abscess

Intramedullary Nonneoplastic Lesion

Prevalence: 4%

  • no cord expansion
  1. Demyelinating disease
  2. Sarcoidosis
  3. Amyloid angiopathy
  4. Pseudotumor
  5. Dural arteriovenous fistula
  6. Cord infarction
  7. Chronic arachnoiditis
  8. Cystic myelomalacia

Cord Lesions

  1. INFLAMMATION
    1. Multiple sclerosis
    2. Acute disseminated encephalomyelitis
    3. Acute transverse myelitis
      • involves half the cross-sectional area of cord
    4. Lyme disease
    5. Devic syndrome
  2. INFECTION
    1. Cytomegalovirus
    2. Progressive multifocal leukoencephalopathy
    3. HIV
  3. VASCULAR
    1. Anterior spinal artery infarct
      • affects central gray matter first
      • extends to anterior two-thirds of cord
    2. Venous infarct / ischemia
      • starts centrally progressing centripetally
  4. NEOPLASM

Intradural Extramedullary Mass!!navigator!!

  1. Nerve sheath tumor (35%)
  2. Meningioma (25%)
  3. Lipoma
  4. Dermoid commonly conus / cauda equina; associated with spinal dysraphism (⅓)
  5. Ependymoma commonly filum terminale; NO spinal dysraphism
  6. Metastasis
    1. “Drop metastases” from CNS tumors
    2. Metastases from outside CNS
  7. Arachnoid cyst
  8. Neurenteric cyst
  9. Hemangioblastoma
  10. Paraganglioma

mnemonic: MAMA N

  • Metastasis
  • Arachnoiditis
  • Meningioma
  • AVM, Arachnoid cyst
  • Neurofibroma

CSF-isointense Focal Spinal Cord Displacement

= space-occupying CSF-isointense intradural / intraspinal extramedullary lesion with widened CSF space

  • nonspecific symptoms: back pain, weakness, numbness, Brown-Séquard syndrome
  1. Epidermoid cyst
  2. Intradural arachnoid cyst
  3. Synovial cyst
  4. Cystic schwannoma
  5. Teratoma
  6. Meningocele
  7. Epidural abscess of spine
  8. Epidural hematoma
  9. Idiopathic spinal cord herniation

Epidural Extramedullary Lesion!!navigator!!

= EXTRADURAL LESIONS OF SPINE

arise from bone, fat, vessels, lymph nodes, extramedullary neural elements

Prevalence: 30% of all spinal tumors

  1. TUMOR
    1. benign
      1. Dermoid, epidermoid
      2. Lipoma: over several segments
      3. Fibroma
      4. Neurinoma (with intradural component)
      5. Meningioma (with intradural component)
      6. Ganglioneuroblastoma, ganglioneuroma
    2. malignant
      1. Hodgkin disease
      2. Lymphoma: most commonly in dorsal space
      3. Metastasis: breast, lung – most commonly from involved vertebrae without extension through dura
      4. Paravertebral neuroblastoma
  2. DISK DISEASE
    1. Bulging disk
    2. Herniated nucleus pulposus
    3. Sequestered nucleus pulposus
  3. BONE
    1. Tumor of vertebra
    2. Spinal stenosis
    3. Spondylosis
  4. INFECTION: epidural abscess / phlegmon
  5. BLOOD: hematoma
  6. OTHERS: synovial cyst, arachnoid cyst, extradural lipomatosis, extramedullary hematopoiesis

mnemonic: MANDELIN

  • Metastasis (drop mets from CNS tumor), Meningioma
  • Arachnoiditis, Arachnoid cyst
  • Neurofibroma
  • Dermoid / epidermoid
  • Ependymoma
  • Lipoma
  • Infection (TB, cysticercosis)
  • Normal but tortuous roots

Anterior Epidural Space Abnormality

  1. NEOPLASM
    Histo: metastases spread from marrow via venous foramina into spinal canal preserving cortex
    • solid enhancement
    • may have central necrosis
    • commonly uni- / bilobed appearance (= preservation of tethered appearance of posterior longitudinal ligament [PLL])
  2. INFECTION
    • frequently central convex appearance (= disruption of posterior vertebral cortex by osteomyelitis)
    1. Epidural abscess
      • peripheral enhancement
    2. Epidural phlegmon
      • solid enhancement
  3. HEMORRHAGE
    • frequently central convex appearance (= disruption of posterior vertebral cortex by fracture)
    • no enhancement
  4. DISK HERNIATION
    • sequestered / extruded disk rarely crosses midline

Cord Atrophy!!navigator!!

  1. Multiple sclerosis
  2. Amyotrophic lateral sclerosis
  3. Cervical spondylosis
  4. Sequelae of trauma
  5. Ischemia
  6. Radiation therapy
  7. AVM of cord

Delayed Uptake of Water-Soluble Contrast in Cord Lesion!!navigator!!

  1. Syringohydromyelia
  2. Cystic tumor of cord
  3. Osteomalacia
    exceedingly rare:
  4. Demyelinating disease
  5. Infection
  6. Infarction

Extraarachnoid Myelography!!navigator!!

  1. SUBDURAL INJECTION
    • spinal cord, nerve roots, blood vessels not outlined
    • irregular filling defects
    • slow flow of contrast material
    • CSF pulsations diminished
    • contrast material pools at injection site within anterior / posterior compartments
  2. EPIDURAL INJECTION
    • contrast extravasation along nerve roots
    • contrast material lies near periphery of spinal canal
    • intraspinal structures are not well outlined

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