Medias Ti No

MEDIASTINAL TUMORS • Mediastinum- Region between the pleural sacs • Tumors arise from anterior, middle & posterior compartments

Extent • Anterior - sternum anteriorly to pericardium & brachiocephalic vessels posteriorly • Middle - between the anterior & posterior compartments • Posterior - pericardium & trachea anteriorly to vertebral column posteriorly

BOUNDARIES OF MEDIASTINUM • • • • •

Anterior - sternum Posterior - Vertebral Column Superior - Thoracic inlet Inferior - Diaphragm ** Mediastinum is connected to neck & retroperitoneum allowing spread of air & infection

ANTERIOR MEDIASTINUM-CONTENTS • • • •

Thymus Anterior mediastinal lymph nodes Internal mammary A & V Pericardial fat

MIDDLE MEDIASTINUM- CONTENTS • Heart & Pericardium, ascending aorta & arch of aorta, vena cavae, brachiocephalic A &V , • phrenic nerve • trachea, main stem bronchi & contiguous lymph nodes • Pulmonary A & V

POSTEIOR MEDIASTINUM-CONTENTS • • • • • •

Descending thoracic aorta Esophagus Thoracic duct Azygos & hemiazygos vein Posterior group of mediastinal nodes Sympathetic trunk & intercostal nerves

CLASSIFICATION • • • • •

Developmental Neoplastic Infectious Traumatic Cardiovascular disorders

ANTERIOR MEDIASTINAL MASSES • • • • •

Thymoma Teratoma Thyromegaly Lymphoma Lipoma, Fibroma - rare

MIDDLE MEDIASTINAL MASSES • Aneurysms - aorta, innominate artery, enlarged pulmonary artery • Lymphadenopathy secondary to carcinoma / metastasis / granulomatosis • Cysts - enteric, bronchogenic, pleuropericardial • Dilated azygos, hemiazygos veins • Hernia of Foramen of Morgagni

POSTERIOR MEDIASTINAL MASSES

• • • • • • •

Neurogenic tumors Meningo-myelocele, meningocele Esophageal - tumor, cyst, diverticula Hiatus hernia Hernia of Foramen of Bochdalek Thoracic spine disease, Extramedullary hematopoiesis

DIAGNOSTIC APPROACH • Imaging - CT, MRI, Radionuclide study, • Tissue sampling - Mediastinoscopy, Thoracoscopy, Needle aspiration, Open Biopsy • Barium study for hernia, achalasia, diverticula • I-131 for intrathoracic goiter

DIAGNOSTIC APPROACH • Mediastinoscopy or anterior mediastinotomy can definitively diagnose anterior & middle mediastinal masses • Video assisted thoracoscopy plays an important role in diagnosis

TREATMENT & PROGNOSIS • Dictated by the etio-pathology of the mass

POSTERIOR MEDIASTINAL NEUROGENIC TUMORS • • • • •

Neurilemmoma Neurofibroma Neurosarcoma Ganglioneuroma Phaeochromocytoma

ROLE OF MRI • • • •

Distinction between vessels and masses no need for contrast better delineation of hilar structures images in multiple planes unlike CT which does axial imaging only

CT • 10% dumbbell tumors present with cord compression • CT scan is essential to rule out intraspinal extension along nerve roots - dumbbell tumors

CLINICAL FEATURES • Nospecific-> mass effect on sorrounding structures • Insidious onset of retrosternal chest pain, dyspnea , dysphagia • 50% are asypmtomatic • mass detected on CXR • Physical findings depend on nature & location of mass

OTHER DIAGNOSTIC STUDIES • Doppler Ultrasonography or Venography of brachiocephalic veins • Arteriography

EPIDEMIOLOGY • Neurogenic tumors are common in children • 50% mediastinal masses are malignant in children • 15% mediastinal masses are malignant in adults

NEUROGENIC TUMORS • Origin - Embryonic neural crest cells around spinal ganglia from sympathetic or parasympathetic components • In paravertebral sulci in association with intercostal nerves • Can arise from vagus & phrenic nerves

NEUROGENIC TUMORS • • • •

Can be ASYPMTOMATIC Cord compression, Chest pain, dyspnea, hoarse voice Horner’s syndrome - unusual

NERVE SHEATH TUMORS • Neurilemmoma( Schwannoma) • well encapsulated , gray- tan, firm, - common • Neurofbroma - 25-40% have VonRecklinghausen’s disease • Neurogenic Sarcoma- at extremes of age • Malignant Schwannoma • Malignancy - 10-20% associated with VR disease

TREATMENT • Resection by Thoracotomy or Video Assisted Thoracoscopic Surgery • Post-op radiation for malignant tumors

UNIQUE CASE • Our patient had the mass for 40 years and suddenly found to grow in size; • So it was resected for suspicion of malignant transformation; • Histopathology proved it to be benign

REFERENCES • Fishman’s - Pulmonary Diseases & Disorders, 3rd ed, Ch. 96, Acquired lesions of Mediastinum- benign & malignant, John R Roberts, Larry R Kaiser, p 1509-1536 • Manual of Clinical Problems in Pulmonary Medicine, 4th ed, 101, Mediastinal masses, Stephen P Bradley, p 482484 • Comprehensive Respiratory Medicine, R Albert, S Spiro, J Jett, Sec 18, ch 74. 1-10, Disorders of Mediastinum