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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 LesionsFocal vs Diffuse

Thymoma

Anthrax

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 MediastinumAnterior 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 T-cell Lymphoma

Mediastinal Lesions• Anterior lesions –

thymoma, thyroid lesions, teratoma, t-cell lymphomas, and lymphadenopathy.

• Usually seen in retrosternal space.

anterior lesion.

Lymphoma

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

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

Mediastinal Lymphadenopathy

• Infection- Pneumonia, TB, Anthrax

• Inflammation -Sarcoidosis

• Malignancy- Lymphoma, Metastatic

4. Posterior Mediastinum

Posterior 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

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

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

ChildrenChildren AdultAdult

•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

Ganglioneuroma Ganglioneuroma GanglioneuroblastGanglioneuroblastomaoma

NeuroblastomaNeuroblastoma

•Most common Most common

•< 20 yrs age< 20 yrs age

•Posterior Posterior mediastinummediastinum

•Sex : equal Sex : equal

•EncapsulatedEncapsulated

•Slow growingSlow growing

•Benign, May Benign, May be malignantbe malignant

•Rare tumour in adultsRare tumour in adults

•50% in first 3 yr of age50% in first 3 yr of age

•Majority occur in Majority occur in adrenal medullaadrenal medulla

•Equal among both sex Equal among both sex

•Often pear shaped or Often pear shaped or lobulatedlobulated

•Majority are Majority are encapsulatedencapsulated

•Must be regarded as Must be regarded as malignantmalignant

•Adults rarely Adults rarely

•Within Within 22 yrs , yrs ,

•Posterior mediastinumPosterior mediastinum

•Adrenal medulla, 20% Adrenal medulla, 20% in thoraxin thorax

•RetroperitonealRetroperitoneal

•Equal in both sexesEqual in both sexes

•Radio-logically less Radio-logically less well definedwell defined

•Highly malignantHighly malignant

•Locally invasiveLocally invasive

•Spontaneous Spontaneous regression may occurregression 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

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– Mature cystic teratoma

• Malignant– Seminomatous* : – Non Seminomatous*

Anterior mediastinal massTeratoma

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 nodesLymphoma

Anterior mediastinal nodesLymphoma

Mediastinal Mesenchymal tumours

Benign Lipoma

Hemangioma

Lymphangioma

Cystic hygroma

Malignant Liposarcoma

Leiomyosarcoma

Rhabdomyosarcoma

Hemangiosarcoma

Angiolipoma

Developmental Mediastinal cysts

• Congenital ; 16%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 / 1000001 / 100000 per year • 70%70% occur in right

cardiophrenic angle– Usually anterior

• Male : Female 1 :1• All ages • 5 – 255 – 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

Pericardial Cyst

Bronchogenic 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. 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