Schwannoma

Epidemiology

  • Most common of all neural tumors
  • The most common causes of posterior mediastinal masses in adults are neurogenic tumors, accounting for more than 80%
  • Neurogenic tumors of the mediastinum comprise 20% of adult and more than 35% of pediatric mediastinal tumors
  • Age: most commonly develop in patients in their 30s or 40s
  • Sex: equal sex predilection

Physiology

  • Benign lung neoplasm
  • Arise from nerve root (and contain only Schwann cells)
  • Typically arise from sympathetic and parasympathetic ganglia or from peripheral nerves of the spinal ganglia
    • They are most commonly located posteriorly
  • Rarely arise from vagus or phrenic nerves

Pathology

  • Composed of Schwann cells with surrounding reticular tissue

Diagnosis

  • CXR/Chest CT Pattern:
    • Solitary Lung Nodule (usually well-defined):
      • Location: no lobar predilection
      • Calcification: rare
      • Cavitation: none
    • Posterior Mediastinal Mass:
      • Well rounded circumscribed mass, usually located contiguous to the vertebral body in the intercostal or paravertebral spaces
      • Sometimes an hourglass shaped lesion can develop
  • MRI: T1-weighted magnetic resonance imaging is helpful in determining vertebral column and spinal cord involvement

Clinical Presentations:

  • Lung Nodule (see [[Lung Nodule or Mass]])
    • Usually asymptomatic
  • Posterior Mediastinal Mass (see [[Mediastinal Mass]])
    • Almost always benign (but may be malignant in some cases)
    • Asymptomatic: often
    • Chest Wall Pain:
    • Cough:
    • Horner’s Syndrome: in rare instances
    • Neurologic Symptoms: parasthesias in UE consistent with a radiculopathy

Treatment

  • Surgical resection via thoracoscopy or thoracotomy: treatment of choice

References

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