Schwannoma (Mediastinal Mass)

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Transcript of Schwannoma (Mediastinal Mass)

  • 1.

2. 3. 4. 5. Evaluation of Mediastinal Mass Leslie Proctor, M.D. November 21, 2008 6. Mediastinal Anatomy

  • Includes structures bound by:
    • the thoracic inlet
    • diaphragm
    • sternum
    • vertebral bodies
    • and pleura
  • Has 3 compartments
    • Anterior
    • Middle
    • Posterior

7. The differential diagnosis of a mediastinal mass depends upon the anatomic compartment in which it arises. Redrawn from Baue, AE, et al. Glenn's Thoracic and Cardiovascular Surgery. 5th ed. Appleton & Lange, Norwalk, CT, 1991. 8. Mediastinal Anatomy

  • Anterior Compartment includes:
  • Thymus
  • Extrapericardial aorta and its branches
  • The great veins
  • Lymphatic tissue.
  • Middle Compartment is bounded by:
  • The pericardium anteriorly
  • The posterior pericardial reflection
  • The diaphragm
  • The thoracic inlet.
  • This compartment includes the heart, intrapericardial great vessels, pericardium, and trachea.
    • Extends from the posterior pericardial reflection to the posteriorborder of the vertebral bodies and from the first rib to thediaphragm.
    • It includes the esophagus, vagus nerves, thoracic duct, sympatheticchain, and azygous venous system

Posterior Compartment: 9. Anatomic Distribution of Masses

  • Anterior Mediastinum
  • Thymic tumors and cysts
  • Germ cell tumors
  • Lymphomas
  • Intrathoracic goiter and thyroid tumors
  • Parathyroid adenomas
  • Connective tissue tumors
    • lipomas and liposarcomas
    • lymphangiomas
    • hemangiomas
  • Thymoma

10. Anatomic Distribution of Masses

  • Middle Mediastinum
  • Thyroid tumor or goiter
  • Tracheal tumors
  • Aortopulmonary paraganglioma
    • paracardial cysts
    • bronchogenic cysts
    • lymphoma
  • Lymphadenopathy
  • Retrosternal Goiter

11. Anatomic Distribution of Masses

  • Posterior Mediastinum
  • Neurogenic tumors
    • including Schwannomas
  • Esophageal tumors
  • Hiatal Hernias
  • Neurenteric Cysts
  • And rarely
    • extramedullary hematopoiesis
    • pancreatic pseudocyst
    • achalasia
  • Paraspinal Ganglioneuroma

12. About Neurogenic tumors

  • 9 to 39 percent of all mediastinal tumors
  • develop from mediastinal peripheral nerves, sympathetic and parasympathetic ganglia, and embryonic remnants of the neural tube.
  • most frequent in the posterior compartment of the mediastinum
  • Cancause neurologic symptoms by compression.
  • Benign Schwannoma is most common
    • often asymptomatic, but can be associated with Horners or Pancoasts syndrome
    • Focal calcifications and cystic changes
    • can extend through an intervertebral foramen, resulting in dumbbell-shaped tumors, and neurologic symptoms of spinal cord compression
    • Gross Histology
      • encapsulated, solid, soft, yellow-pink nodule, with the capsule attached to the epineurium of the nerve that gives rise to the neoplasm
    • Microscopic histology
      • composed of spindle cells with elongated nuclei, forming interlacing bundles with focal nuclear palisading
      • nuclear atypia, and stromal sclerosis in older lesions
      • Mitotic figures are rare.
      • Immunohistochemical studies reveal a strongly positive reaction with S-100 protein.

13. Mediastinal Benign Schwannoma 14. Anatomic Distribution of Masses

  • A mass may extend beyond these boundaries as it grows in size
  • In adults, anterior compartment masses are more likely to be malignant

15. Age Distribution

  • Age can help predict etiology of the mass
    • infants and children, neurogenic tumors and enterogenous cysts are the most common mediastinal masses
    • In adults, neurogenic tumors, thymomas, and thymic cysts are most frequently encountered lesions
    • In 20-40 year olds, the likelihood of a mass being malignant is greater secondary to the increased incidence of lymphoma (Hodgkins and non-Hodgkin's) and germ cell tumors

16. Signs and Symptoms

  • Depend on location of mass
  • Asymptomatic
  • Vague symptoms
    • aching pain
    • cough
  • Children more likely to be symptomatic
    • respiratory difficulty
    • recurrent pulmonary infections

17. Signs and Symptoms

  • Airway compression
    • recurrent pulmonary infection
    • hemoptysis
  • Esophageal compression
    • dysphagia
  • Involvement of the spinal column
    • paralysis
  • Phrenic nerve damage
    • elevated hemidiaphragm

18. Signs and Symptoms

  • Recurrent laryngeal nerve involvement
    • Hoarseness
  • Sympathetic ganglion involvement
    • Horners Syndrome
      • Ptosis, miosis, anhidrosis
  • superior vena cava involvement
    • Superior vena cava syndrome
      • facial neck, and UE swelling, dyspnea,chest and UE pain, mental status changes

Horners Syndrome 19. Signs and Symptoms

  • Can also be associated with systemic diseases
    • Thymoma: myasthenia gravis, immune deficiency, red cell aplastic anemia
    • Goiter: thyroxicosis
    • Thymic carcinoid: Cushings syndrome
    • Parathyroid: hyperparathyroidism

20. Evaluation: Imaging

  • 2 view PA/Lat Chest X-ray
    • comparisons with old x-rays important
  • Chest CT with contrast
    • most important method of evaluation
    • Can help determine location, morphology, size, and attenutation coefficient
    • Important for directing further therapy
  • MRI
    • when contrast allergy or renal failure present
    • when vascular or chest wall involvement is suspected
    • neurogenic tumors (especially helpful in detecting intraspinal component
  • Ultrasound
    • Differentiate cystic from solid masses and relate to surrounding structures
    • When mass is close to heart or pericardium
    • Transesophageal or transbronchial useful to evaluate lymph nodes, sometimes for biopsy
  • Radio nucleotide scanning
    • With radioactive iodine when thyroid tumor suspected
  • PET scanning
    • Can localize specific tumors (pheochromocytoma, paragangliomas, neuroblastomas, neurogangliomas by targeting their metabolic pathways

21. Evaluation: Laboratory

  • Depends on clinic setting, but may include:
    • Thyroid function tests
      • If goiter suspected
    • Chemistry panel including calcium and phosphate and PTH
      • If parathyroid adenoma suspected
    • Fractionated 24-hour urinary metanephrines and catecholamines
      • If paraganglionic tumor suspected
    • AFP/beta HCG
      • In all males with anterior mediastinal tumor because of concern for non-seminomatous germ cell tumor