7 Mediastinal Syndromes

Mediastinum Division - Superior, - Inferior - Anterior, - Middle, - Posterior compartments. The mediastinum contains all of the vital structures of the chest except the pulmonary parenchyma.

Mediastinal Regions

Mediastinum The superior mediastinum lies between the manubrium and thoracic vertebrae one to four. The anterior mediastinum is bounded by the sternum anteriorly and pericardium posteriorly. The middle mediastinum consists of the heart and vascular structures; anything in the middle of the chest that is radio dense on lateral radiograph is within the middle mediastinum. The posterior mediastinum lies between the heart and the vertebral bodies.

Subdivision of mediastinum anterior mediastinum middle mediastinum posterior mediastinum

Mediastinal Lesions Any lesion that occurs in the mediastinum – can be focal or diffuse. CT scan or MRI with contrast is usually indicated for further evaluation.

Mediastinal Lesions Focal vs Diffuse Anthrax Thymoma in patient with Myasthenia Gravis Anthrax Focal lesions are caused by masses Diffuse lesions are caused by infection, bleeding or infiltrating tumor Thymoma

1. Superior Mediastinum Aortic Arch & its branches Brachiocephalic and subclavian vessels Superior vena cava upper half & tributaries Trachea Thyroid Oesophagus Thoracic duct Phrenic ,Vagus ,Cardiac, Lt.Recurrent L nerves

2. Anterior Mediastinum Anterior mediastinum Anterior Mediastinal Masses Thymus Thyroid Ectopic Thyroid Tissue Parathyroid Gland Internal mammary vessels Lymph nodes Aortic Arch SVC Superior Vena Cava Thymic lesions (and parathyroid masses) Teratomas (and other germ cell tumors) ‘Terrible' lymphoma Tortuous vessels Dissecting aorta, right arch Trauma Aortic aneurysm, Pericardial cyst, Epicardial fat pad Lymphadenopathy. 

Anterior mediastinal mass

Anterior Mediastinal Mass T-cell Lymphoma

anterior lesion. Lymphoma Mediastinal Lesions Anterior lesions – thymoma, thyroid lesions, teratoma, t-cell lymphomas, and lymphadenopathy. Usually seen in retrosternal space. anterior lesion. Lymphoma Pos silhouette sign with L heart border indicating that this is an anterior lesion. Lymphoma in a 13 yr old boy who was complaining of testicular swelling. Since systemic diseases such as lymphoma may present as a testicular mass, a chest radiograph was obtained. The common causes of testicular swelling with a mediastinal mass include lymphoma, leukemia and germ cell tumors.

Mediastinal Lesions Lateral view shows a solid tissue density in the region anterior and superior to the heart. Lymphoma is the most common anterior mediastinal mass. Lymphoma

Middle Mediastinal Mass 3. Middle Mediastinum Middle mediastinum Middle Mediastinal Mass Heart and pericardium Ascending aorta Superior vena cava Azygous vein Phrenic and vagus nerves Trachea Trachea Bifurcation and main bronchi Pulmonary arteries and veins Hilar Lymph Node lymphadenopathy due to metastases or primary tumor.  Other causes include hiatial hernia, aortic aneurysm, Thyroid mass, duplication cyst, and bronchogenic cyst.  

Mediastinal Lesions Middle lesions – thoracic aortic aneurysms, hematomas, neoplasms, lymphadenopathy, esophageal lesions, and diaphragmatic hernias. Enlarged lymph nodes are the most frequent cause of a middle mediastinal mass. lymphadenopathy Mass obscuring the right tracheal border - lymphadenopathy Trachea is located in the middle mediastinum, thus this lesion is also in the middle mediastinum.

Mediastinal Lymphadenopathy Infection- Pneumonia, TB, Anthrax Inflammation -Sarcoidosis Malignancy- Lymphoma, Metastatic

4. Posterior Mediastinum Posterior mediastinal mass Esophagus Thoracic duct Thoracic descending Aorta Descending Azygos Hemiazygos vein Vagus nerves Sympathetic Chain Paravertebral Lymphnode Neurogenic lesions, Neoplasm , Lymphadenopathy , Aortic aneurysm, Adjacent pleural or lung mass, Neurenteric cyst or lateral meningocele, and Extramedullary hematopoiesis

Aneurysm of Descending Aorta Mediastinal Lesions Posterior lesions – Neurogenic lesions, hiatal hernias, descending aortic aneurysm, neoplasms, and hematomas. 90% of posterior lesions are neurogenic lesions. Aneurysm of Descending Aorta Aneurysm of Descending Aorta

Posterior mediastinal masses will give double density over left side of heart.

Origins of Mediastinal Mass Developmental Neoplastic Infectious Traumatic Cardiovascular disorders

Mediastinologists Thoracic Surgeon Pulmonologist ENT Cardiologist Endoscopist Radiologist

Differentials Diaphragmatic lesions; eventration ,hernia Esophageal tumours ,achalasia Mediastinal metastasis Mediastinal lymph nodes: lymphomas, granulomas Thyroid retrosternal extension Aneurysm of aorta Ventricular aneurysm Tracheal , heart tumours

Incidence 1 in 100000 Thrice more common than bronchial adenoma 1/3000 admission at large medical centre Neural commonest 20-27% Thymic second 19-26% Cyst third 18-21% Teratomas \ lymphoma fourth 12% Neural , Thymic, developmental ,Lymphoma :88% of all mediastinal tumours

Children Adult Neural tumours 40% Lymphoma 20% Teratomas & Cysts 10-15% Thymic rare Posterior Mediastinum Most often benign 2/3 of tumors symptomatic Neural tumours 20-27% Thymic 19-26% Cyst third 18-21% Teratoma \ lympho 11-12% Anterior Mediastinum Often Malignant 1/3 of tumors are symptomatic Ages 30 – 50

Malignant Tumors Invasion Structure Tracheobronchial tree and lungs Esophagus Superior Vena Cava Pleura and Chest Wall Intrathoracic nerves

Primary Mediastinal Tumors Neural Nerve sheath Autonomic nervous system Malignant peripheral nerve sheath Granular cell tumour Thymic Thyroid Germ cell tumours Benign Malignant Seminomatous Non seminomatous Lymphomas Developmental cysts Pleuropericardial cysts

Symptoms Cough often recurrent Shortness of Breath may be with wheeze Chest pain Fever Chills Weight loss Night Sweats Hemoptysis Airway compression with Stridor Hoarseness Esophageal compression dysphagia SVC compression …. Neck vein engorgement, facial swelling Rt.ventricular outflow obstn Pericarditis Cardiac temponade Heart failure

Mediastinal Neural tumours Nerve sheath t0 Benign (neurolemmoma) Schwannoma Neurofibroma Malignant peripheral nerve sheath t0 Neurosarcoma Neurofibrosarcoma Neurogenic sarcoma Malignant schwannoma Malignant neurinoma Granular cell tumour Granular cell myoblastoma Autonomic nervous system (neurocyte) Ganglioneuroma Ganglioneuroblastoma Neuroblastoma Paraganglioma Aorticopulmonary Aorticosympathetic

Large Neuroma

Ganglioneuroblastoma Neuroblastoma Ganglioneuroma Ganglioneuroblastoma Neuroblastoma Most common < 20 yrs age Posterior mediastinum Sex : equal Encapsulated Slow growing Benign, May be malignant Rare tumour in adults 50% in first 3 yr of age Majority occur in adrenal medulla Equal among both sex Often pear shaped or lobulated Majority are encapsulated Must be regarded as malignant Adults rarely Within 2 yrs , Adrenal medulla, 20% in thorax Retroperitoneal Equal in both sexes Radio-logically less well defined Highly malignant Locally invasive Spontaneous regression may occur

Intrathoracic Meningocele

Thymus of a Neonate

Thymus Thymic hyperplasia Thymoma Thymic cyst Thymic carcinoma Thymic carcinoid tumours Thymolipoma Germ cell tumours Ectopic parathyroid adenomas Lymphoma Secondary neoplastic

Thymic hyperplasia Nearly always infantile or childhood Usually asymptomatic Pronounced in HIV, SLE,Thyrotoxicosis Indistinct from other thymic t0 on Radio or CT Steroids may reduce Subtotal surgery

Thymoma Epithelial neoplasms most common primary neoplasms of the anterior superior mediastinum Any age , rare <20, nearly all middle-aged adults. Male predominance ½ of the patients are asymptomatic 25-30% of patients have symptoms related to compression of adjacent mediastinal structures including cough, chest pain, and shortness of breath

Thymoma may have myasthenia gravis (30-40%), pure red cell aplasia, hypogammoglobulinemia, endocrine disorders can be completely encapsulated (benign) or locally invasive without a fibrous capsule classified by predominant cell types: epithelial, lymphoid, or Biphasic , mixed or lymphoepithelial type one- third of thymomas are invasive and may grow into the surrounding mediastinal structures,

Thymoma This is determined at surgery and is not a histologic diagnosis, local invasion of the pleura occurs frequently, distant metastases are infrequent Surgical removal enmass with capsule intact Median sterotomy Thoracotomy Transcervical approach Radiotherapy usually reserved for incomplete excission Chemo-sensitive (May be) : cis, doxo, vin, c-phos

Encapsulated thymoma Encapsulated thymoma: 51 y/o asymptomatic male. PA chest radiograph demonstrates a mediastinal mass with smooth borders at the right paracardiac region causing effacement of the right heart border (positive silhouette sign). Contrast-enhanced chest CT (mediastinal window) demonstrates a heterogeneous, right-sided anterior mediastinal mass (*) abutting the right heart border.

Invasive Thymoma

Germ cell tumours As a result of the proliferation of the primary extragonadal germ cell Mostly found near the midline Adults :anterior mediastinum Child : sacrococcygeal area

Germ cell tumours Benign Malignant Mature cystic teratoma Seminomatous* : Non Seminomatous*

Anterior mediastinal mass Teratoma

Malignant Germ cell tumours Seminomatous* : Seminoma Exclusively young male 20-40 yrs 1/3 asymptomatic , Chest pain, dysponea, SVC obstruction Radio ; lobulated , non cacified ,anterior mediastinal Normal serum AFP USG testicle discrete hypoecoic masses,with microcalcifictions Treatment ; chemotherapy* , Radio or combi Et +cis *4 cycle or Et +cis +bleo * 3 cycles Highly radiosensitive radio reserved for bulky

Mediastinal Lymphoma Mediastinum is involved in 50% Hodgkin’s diseases Most cases are of nodular sclerosing type Treatable and many are curable too Intensive chemotherapy or radiotherapy or both Radio alone relapse 50-74% Chemo alone relapse 33-50% “MOPP” or “DBVD” followed by radio preferred

Anterior mediastinal nodes Lymphoma

Anterior mediastinal nodes Lymphoma

Mediastinal Mesenchymal tumours Benign Lipoma Hemangioma Lymphangioma Cystic hygroma Malignant Liposarcoma Leiomyosarcoma Rhabdomyosarcoma Hemangiosarcoma

Angiolipoma

Developmental Mediastinal cysts Congenital ; 16% of all mediastinal cyst Foregut duplication largest group Pleuropericardial next to it

Pleuropericardial cysts Synonyms Pericardial cyst Coelomic cyst Spring water cyst Hydrocele of mediastinum 1 / 100000 per year 70% occur in right cardiophrenic angle Usually anterior Male : Female 1 :1 All ages 5 – 25 cms Soft , unilocular Crystal clear spring water , transudate with acellular & little proteins Asymptomatic Chest pain Radiograph Sharply demarcaed Rounded Smooth edged Anterior mass

Middle Mediastinal Cysts Bronchogenic Cyst Pericardial Cyst

Aortic aneurysm

Diagnostic of mediastinal masses Chest X-Rays CT ( Computed Tomography)/MRI Most valuable for diagnosis Done in most of cases CT guided needle biopsy Mediastinoscopy / ant. mediastinotomy Definite diagnosis Mediastinoscopy/ant. medistinotomy with biopsy Definite with establishing the disease diagnosis Radionuclide Scanning Goiter Barium studies For: hernia,diverticuli,achalasia Percutaneous fine needle biopsy endoscopic ultra sound guided biopsy Video assisted thoracoscopic removal of mass

Mediastinoscopy

Mediastinoscopy: Overused, Invasive, Limited Applications

Mediastinoscopy: Invasive, requires general anesthesia Mediastinoscopy: Invasive, requires general anesthesia. Subcarinal  and subaortic (a-p window) nodes inaccessible.

Thoracoscopy: Limited to inferior mediastinum

Thoracoscopic biopsy (video-assisted thoracoscopy) Limited to inferior mediastinum.

Endoscopic Ultrasound: No incision, no anesthesia

Endoscopic ultrasound guided biopsy of mediastinal lesions has a major impact on patient management. It is a safe and sensitive minimally invasive method for evaluating patients with a solid lesion of the mediastinum suspected by CT scanning. It has a significant impact on patient management and should be considered for diagnosing the spread of cancer to the mediastinum in patients with lung cancer considered for surgery, as well as for the primary diagnosis of solid lesions located in the mediastinum adjacent to the oesophagus. Thorax 2002 Feb;57(2):98-103

“Endoscopic ultrasonography also provides information helpful for clinical staging of lung cancer and is the procedure of choice for performing fine-needle aspiration biopsy of posterior mediastinal and subcarinal lymph nodes.” AJCC manual 2007

CT scan or MRI CT scan or MRI with contrast is always indicated for further evaluation. MRI is preferred for neurogenic lesions but obtaining a CT scan is never wrong with a mediastinal mass. CT-guided transthoracic fine needle aspiration (FNA): Limited by surrounding vascular structures, size of the targeted lesion. Pneumothorax risk.

Prognosis Varies depending on type of tumors and resection. Benign tumors – excellent prognosis Malignant tumors – depends on the type