Evaluation of Mediastinal Mass

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.