E N D
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
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.
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
Can cause neurologic symptoms by compression.
Benign Schwannoma is most common
often asymptomatic, but can be associated with Horner’s or Pancoast’s 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 (Hodgkin’s 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
Horner’s 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
19. Signs and Symptoms Can also be associated with systemic diseases
Thymoma: myasthenia gravis, immune deficiency, red cell aplastic anemia
Goiter: thyroxicosis
Thymic carcinoid: Cushing’s 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
22. Management Tailored to specific or likely diagnosis
Must decide whether to excise, biopsy, or aspirate lesion
Excision should be done with teratomas, thymomas, and isolated masses likely to be benign (VATS, median sternotomy, thoracotomy)
Needle aspiration of cystic lesions
Diagnostic biopsy is procedure of choice when suspect lymphoma, germ cell tumor, or unresectable invasive malignancy
24. References Kallab, Andre MD. Superior Vena Cava Syndrome. Emedicine. August 10 2005. http://www.emedicine.com/MED/topic2208.htm
Gangadharan, Sidhu MD. Evaluation of Mediastinal Masses. UptoDate. October 7, 2008.
Parmar, Malvinder S, MB, MS. Horner’s Syndrome. Emedicine. June 5, 2008. http://www.emedicine.com/med/TOPIC1029.HTML
Strolls, DC, Rosado-de-Christenson, ML, Jett, JR. Primary mediastinal tumors. Part I: Tumors of the anterior mediastinum. Chest 1997; 112:511.
Strollo, DC, Rosado-de-Christenson, ML, Jett, JR. Primary mediastinal tumors: Part II. Tumors of the middle and posterior mediastinum. Chest 1997; 112:1344.
Medscape.com (multiple images)
Devouassoux-Shisheboran, Mojgan MD and Travis, William D MD. Pathology of Mediastnal Tumors. Uptodate. September 9th, 2008.