Enlarged Neural Foramen
Bryson Borg, MD
DIFFERENTIAL DIAGNOSIS
Common
Nerve Sheath Tumor
Schwannoma
Neurofibroma
Perineural Root Sleeve Cysts
Dural Dysplasia
Lytic Metastasis to Vertebral Body or Pedicle
Less Common
Osteomyelitis, Granulomatous
Neuroblastic Tumor
Post-Traumatic Pseudomeningocele
Meningocele, Lateral
Vertebral Artery Ectasia or Aneurysm
Osteolytic Primary Bone Tumor
Aneurysmal Bone Cyst
Plasmacytoma
Rare but Important
Hypoplastic or Absent Pedicle
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
CT useful to distinguish bony remodeling (benign or low grade mass) from osteolysis (aggressive neoplasm, infection)
Helpful Clues for Common Diagnoses
Nerve Sheath Tumor
Transforaminal “dumbbell-shaped” enhancing soft tissue mass
Perineural Root Sleeve Cysts
Circumscribed foraminal masses, often multiple, tend to be small (1-3 cm)
Contents follow CSF, no enhancement, ± opacification with myelography
Dural Dysplasia
Transmission of chronic CSF pressures by weakened dura leads to bony remodeling and expansion of lumbosacral canal and neuroforamina
Can be seen with neurofibromatosis type 1, Marfan disease, homocystinuria, Ehlers-Danlos, and ankylosing spondylitis
Lytic Metastasis to Vertebral Body or Pedicle
Destructive process with loss of cortex, wider zone of transition to normal bone, multiple osseous lesions
Renal, lung, and breast are common primaries to develop osteolytic metastases
Helpful Clues for Less Common Diagnoses
Osteomyelitis, Granulomatous
Tuberculosis may present with osteolytic lesion of the neural arch
Also: Brucellosis, coccidioidomycosis, blastomycosis, actinomycosis
Neuroblastic Tumor
Paravertebral mass ± transforaminal and epidural extension
Foraminal enlargement by remodeling or bony destruction
Post-Traumatic Pseudomeningocele
Cystic transforaminal structure, neural elements usually absentRelated posts:
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