Expansile Lesion of Vertebra

1. INVOLVEMENT OF MULTIPLE VERTEBRAE
   Metastases, multiple myeloma / plasmacytoma, lymphoma, hemangioma, Paget disease, angiosarcoma, eosinophilic granuloma
2. INVOLVEMENT OF ≥2 CONTIGUOUS VERTEBRAE
   Osteochondroma, chordoma, aneurysmal bone cyst, myeloma
3. BENIGN LESION
   1. Osteochondroma (1–5% of solitary osteochondromas, 7–9% in hereditary multiple exostoses) commonly arising from posterior elements, esp. C2
   2. Osteoblastoma (30–40% in spine) M÷F = 2÷1; equal distribution in spine; posterior elements (lamina, pedicle), may involve body if large; expansile lesion with sclerotic / shell-like rim, foci of calcified tumor matrix in 50%; younger patient
   3. Giant cell tumor (5–7% in spine) commonly sacrum, expansile lytic lesion of vertebral body with well-defined borders; secondary invasion of posterior elements; malignant degeneration in 5–20% after radiation therapy
   4. Osteoid osteoma (10–25% in spine) commonly lower thoracic / upper lumbar spine, posterior elements (pedicle, lamina, spinous process)
      • younger patient
      • painful scoliosis with concavity toward lesion
      • involvement of pedicle + lamina (in 63%)
      • extending anteriorly affecting ⅓ to ⅔ of posterolateral vertebral body
      • sparing of intervertebral disk space
      • edema in neural arch at adjacent level possible
   5. Aneurysmal bone cyst (12–30% in spine) thoracic >lumbar >cervical spine, posterior elements with frequent extension into vertebral bodies, well-defined margins, may arise from primary bone lesion (giant cell tumor, fibrous dysplasia) in 50%, may involve two contiguous vertebrae
   6. Hemangioma (30% in spine) 10% incidence in general population; commonly lower thoracic / upper lumbar spine, vertebral body, “accordion” / “corduroy” appearance
   7. Hydatid cyst (1% in spine) slow-growing destructive lesion, well-defined sclerotic borders, endemic areas
   8. Paget disease vertebral body ± posterior elements, enlargement of bone, “picture framing”; bone sclerosis
   9. Eosinophilic granuloma (6% in spine) most often cervical / lumbar spine; multiple involvement common
      • vertebra plana / incomplete collapse of vertebra
      • absence of osteolytic area
      • preservation of posterior elements + pedicles
   10. Fibrous dysplasia (1% in spine) vertebral body, nonhomogeneous trabecular “ground-glass” appearance
   11. Enostosis (1–14% in spine)
       location: T1–T7 >L2–L3
4. MALIGNANT LESION
   1. Chordoma (15% in spine)
      • Most common nonlymphoproliferative primary malignant tumor of the spine in adults
      
      location: particularly C2, within vertebral body; violates disk space
   2. Chondrosarcoma (3–12% in spine)
      • 2^nd most common nonlymphoproliferative primary malignant tumor of the spine in adults
      
      Mean age: 45 years; M >F
      location: thoracic spine (mostly)
      Site: vertebral body (15%), posterior elements (40%), both (45%)
      • pain (95%); palpable mass (28–82%)
      • neurologic symptoms (45%)
      • large calcified mass with bone destruction
      • involvement of adjacent vertebra by extension through disk (35%)
   3. Metastasis: osteolytic, osteoblastic
   4. Multiple myeloma / plasmacytoma
      Clue: vertebral pedicles usually spared
      • single vertebral collapse as usual manifestation
      • “minibrain” appearance on axial CT = hollow vertebral body / pedicle + cortical thickening
      
      Characteristics suggestive of multiple myeloma:
      • sharply demarcated scalloped lytic lesions
      • marked osteoporosis
      • “cold” lesions on bone scans
      • lack of a primary neoplasm
   5. Angiosarcoma
      10% involve spine, most commonly lumbar
   6. Ewing sarcoma and PNET
      • Most common nonlymphoproliferative primary malignant tumor of the spine in children; metastases more common than primary
        Site: vertebral body with extension to posterior elements
      • diffuse sclerosis + osteonecrosis (69%)
   7. Osteosarcoma (4% in spine)
      Average age: 4^th decade; M >F
      Histo: mostly osteoblastic
      location: thoracic + lumbar segments
      Site: vertebral body, posterior elements (79%)
      • neurologic symptoms
      • may present as “ivory vertebra”
   8. Lymphoma
      Peak age: 5^th–7^th decade; M÷F = 8÷1
      location: paraspinal, vertebral, epidural
      Site: tumor spread from medullary cavity along small vascular channels
      • lytic in NHL
      • sclerotic “ivory vertebra” or mixed pattern in HD
      • ↑radionuclide uptake on bone scintigraphy