CASE SERIES OF MEDIASTINAL MASSES – A SINGLE INSTITUTIONAL EXPERIENCE Dissertation submitted for M.Ch DEGREE EXAMINATION BRANCH I – CARDIOTHORACIC SURGERY MADRAS MEDICAL COLLEGE AND GOVERNMENT GENERAL HOSPITAL CHENNAI – 600 003 THE TAMILNADU DR.M.G.R MEDICAL UNIVERSITY CHENNAI – 600 032 AUGUST 2009 CORE Metadata, citation and similar papers at core.ac.uk Provided by ePrints@TNMGRM (Tamil Nadu Dr. M.G.R. Medical University)
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CASE SERIES OF MEDIASTINAL MASSES – ASINGLE INSTITUTIONAL EXPERIENCE
Dissertation submitted for
M.Ch DEGREE EXAMINATION
BRANCH I – CARDIOTHORACIC SURGERY
MADRAS MEDICAL COLLEGE
AND
GOVERNMENT GENERAL HOSPITAL
CHENNAI – 600 003
THE TAMILNADU DR.M.G.R MEDICAL UNIVERSITY
CHENNAI – 600 032
AUGUST 2009
CORE Metadata, citation and similar papers at core.ac.uk
Provided by ePrints@TNMGRM (Tamil Nadu Dr. M.G.R. Medical University)
A great many people made this work possible. I thank my Dean forallowing me to conduct this study.
My warmest respects and sincere gratitude to our belovedProf.M.Varadharajan, Professor and Head of the Department of
Cardiothoracic Surgery, Government General Hospital, Chennai whowas the driving force behind this study. But for his constant guidance
this study would not have been possible.
I am indebted to Prof.M.Varadharajan for his constructive ideas,guidance and personal involvement in this study.
I am grateful to Prof. Karkuzhali, M.D., Professor and Head of theDepartment of Histopathology, Government General Hospital, Chennai
who helped me in this study.
My respectful thanks to Prof.T.S.Manoharan, Prof.S.Vishwakumar,Prof.T.A.Vijayan, Prof.K.Sundaram, Prof.K.Raja Venkatesh, without
whom much of this work would not have been possible.
In addition, I am grateful to Dr.R.K.Sasankh, Dr.N.Nagaraj,Dr.B.Mariappan, Dr.T.M.Ponnuswamy, Dr.Dhamodharan,
Dr.PonRajarajan, Dr.Raghavendran for their invaluable contributionfor my study.
Last but not the least; I thank all my patients for their kind cooperation
CONTENTS
Page
1. Introduction 1
2. Review of Literature 3
3. Aims and Objectives 32
4. Materials and Methods 33
5. Observations & Results 34
6. Discussion 48
7. Summary & Conclusion 54
8. Proforma
9. Bibliography
10. Master Chart
CERTIFICATE
This is to certify that the dissertation entitled “CASE SERIES
OF MEDIASTINAL MASSES – A SINGLE INSTITUTIONAL
EXPERIENCE” presented here is the original work done by
Dr.G.K.Jaikaran in the department of cardio thoracic surgery,
Government General Hospital, Madras Medical college, Chennai
600003, in partial fulfillment of the University rules and regulations for
the award of M.Ch Cardiothoracic degree under our guidance and
supervision during the academic period from 2006 - 2009.
Dean,Madras Medical college,
Chennai.
Professor and Head,Department of Cardiothoracic surgery,
Government general hospital,Chennai 600003.
Introduction
The mediastinum is an extremely important and complex part of
the thorax because it contains a variety of important organs and
anatomic structures. Many histologically different neoplasms and cysts
that affect people of all ages arise from the multiple anatomic structures
present in the mediastinum.Because this area is also the site of
numerous lymph nodes, metastases secondary to lesions in other parts
of the body are also frequently found. Both benign and malignant
lesions are being recognized with increasing frequency, and a
differential diagnosis is important whenever possible. The incidence
and types of the many primary mediastinal tumors and cysts vary with
the age of the patient group under consideration. In infants and
children, neurogenic tumors are the most common, followed by
lymphomas, foregut cysts, and benign germ cell tumors. In adults,
thymic tumors are the most common surgically treated mediastinal
tumors. Treatment strategies for mediastinal tumors and cysts are quite
broad, depending on the nature of the disease (1).
Major changes have recently occurred in the clinical
presentation, diagnosis, and management of primary lesions of the
mediastinum. New diagnostic techniques and improved therapy have
led to more objective preoperative diagnoses as well as better longterm
results.
Mediastinal masses are the lesions in the thoracic space bounded
superiorly by the thoracic inlet; inferiorly by the diaphragm , anteriorly
by the sternum posteriorly by the spine, laterally bounded by the pleural
spaces, including the mediastinal pleura.
Review ofLiterature
ANATOMICAL PERSPECTIVES:
The mediastinum is strategically located from the thoracic inlet
to the diaphragm between the left and right pleural cavities and contains
vital structures of the circulatory, respiratory, digestive and nervous
systems. Embryologic development leads to cells from ectodermal,
mesodermal and endodermal origin ultimately residing in the small
mediastinal compartment. Clinically the mediastinum may be divided
into superior and inferior compartments with the inferior mediastinum
being subdivided into anterior, middle and posterior sections. The
topographic landmarks in each division of the mediastinum allow for
directed investigative, diagnostic and therapeutic strategies (2) .
The mediastinum (from the Greek medium istemi) is an anatomic
region localized at the center of the thorax, limited in front by the
sternum, in the back by the spine and laterally by the lungs with their
pleural lining. There are several classifications for the mediastinum,
although it is Shield who classically divided this region into three areas:
anterior, visceral and posterior limited by two frontal planes. The first
tangent to the anterior surface of the pericardium and the large vessels,
the second tangent to the anterior surface of the vertebral bodies.
Thymus is found in the anterior mediastinum with the internal
mammary vessels, the lymph nodes, connective tissue, fat-cell tissue,
the lower pole of thyroid and the ectopic parathyroids.
In the visceral compartment there are the heart and pericardium
the great vessels ascending, and descending aorta, the aortic arch with
the supraortic vessels, the pulmonary artery with the proximal segment
of their branches, the distal segments of the pulmonary veins, the
superior vena cava with the brachiocephalic trunks, the azygos vein,
and Botallo’s ligament or Botallo’s pervious duct the thoracic duct
nerves: vagus, phrenic, recurrent laryngeal, lymph node chains and the
anterior surface of the vertebral bodies.
In the posterior compartment there are the lateral surface of the
vertebral bodies, the internal surface of the intercostal muscles, the
proximal segment of the intercostal nerves, the sympathetic chain with
its ganglions and hemiazygos vein. The wide variety of mediastinal
masses different for embryological origin, anatomic constitution,
location and functional features are responsible for the various signs
and symptoms which are collectively called the mediastinal syndrome,
which are due to compression, obstruction or infiltration of the mass
over near structures. The mediastinal syndrome includes all
the symptoms caused by the pathological environment of all
mediastinal
structures and systems, the cardiovascular, respiratory, digestive and
lastly the peripheral and central nervous system. It can be total,
affecting all three compartments or partial, with anterior, median or
posterior mediastinal syndrome. In addition, it is important to mention
systemic syndromes associated with tumoral masses and syndromes of
endocrinal hypersecretion caused by tumors.
ANTERIOR MEDIASTINAL TUMORS:
• Thymic tumors
• Lymphoma
• Germ Cell Tumors
• Endocrine tumors
• Mesenchymal tumors
THYMIC TUMORS :
• Incidence – 15 per 1 lakh per person per year
• 50% of anterior mediastinal tumors
• 30% in adults and 15% in children
• Various lesions
o Thymic Hyperplasia
o Thymoma
o Thymic cyst
o Thymolipoma
o Thymic Carcinoma
o Thymic Neuroendocrine tumors
• Developed as pairs of epithelial anlagen in ventral portion of
third pharyngeal pouch.
• Histology
o 6 types - 4 in cortex , 2 in medulla
o Type 6 cells are called Hassals Corpuscles
Classification of thymic tumors
• Rosal and Levine Classification
• Marino and Muller Hermeling
• WHO Staging
• Masoaka staging – provides more precious prognostic
information
Associated diseases
• Myasthenia
• Cytopenia
• SLE, RA, Polymyositis.
MYASTHENIA GRAVIS:
Most common associated disease with thymoma is myasthenia
gravis, 5 to 15 % of myasthenia gravis are found to have thymomas. 30
to 50 % of thymomas are associated with clinical myasthenia gravis
The disease may develop later even after thymectomy, for this reason it
is essential that complete thymectomy be performed as a part of
resection of any anterior mediastinal tuimors that may present as
thymoma.
GERM CELL TUMORS:
Anterior mediastinum is the most common location for
occurence of extra gonadal germ cell tumors accounting for 15 to 20%
of all anterior mediastinal masses.
• Benign mediastinal teratoma
Accounts for 60% of mediatinal germ cell tumors Usually
asymptomatic in adults
Presents in children due to airway compression
• Malignant mediastinal teratoma
Seminomatous – 40%
Non seminomatous – 60 % - Embryonal cell carcinoma
- Choriocarcinoma
- Yolkm Sac tumor
- Teratocarcinoma
These generally present as diffuse non discrete anterior
mediastinal masses. Serum levels of AFP , B-HCG , LDH may be
helpful.
MIDDLE MEDIASTINAL TUMORS
• Cysts
• Lymphomas
• Mesenchymal tumors
• Carcinoma
LYMPHOMAS:
The mediastinum is commonly involved by malignant
lymphomas. Most mediastinal lymphomas occur in the anterior or
middle mediastinal compartments. They usually arise from mediastinal
lymph nodes but may arise from the thymus gland or other mediastinal
structures. About 50% of Hodgkin’s disease and 20% of non-Hodgkin’s
lymphomas present as mediastinal lymphomas. The size of the mass
dictates whether symptoms are present. Bulky mediastinal disease
usually causes compression symptoms. Patients commonly have chest
pain or heaviness and cough. Dyspnea may result from large airway
compression, lung compression, pleural effusion or pericardial effusion.
Due to the right sided predominance of paratracheal lymph nodes, SVC
syndrome is relatively common (20–60% of patients), especially in
those with non-Hodgkin’s lymphoma. Diagnosis of Hodgkins is proven
by the presence of Reed Sternberg cells. Management is basically
chemotherapy / radiotherapy.
CYSTIC LESIONS
20% of all mediastinal masses. Common in the middle
mediastinum and rarely in the posterior mediastinum which comprises
of
• Bronchogenic cyst
• Hydatid cyst
• Enteric cysts
• Intramural esophageal
• Neuro enteric cysts
Bronchogenic cysts : 60 % of mediatinal cysts. Part of spectrum of
broncho pulmonary foregut abnormalities including extralobar,
intralobar sequestration and congenital cystic adenomatoid
malformation. Presents as chest pain , cough, hemoptysis. The cyst is
lined by ciliated columnar epithelium and excision in toto is the
treatment of choice.
Gastroenteric sycts : These are duplication cysts, which are peri
esophageal lesions that form from posterior division of primitive
foregut. May arise in middle or posterior mediastinum lined by non
keratinizing squamous ciliated columnar gastric or small intestinal
epithelium. Presents as cough or dyspnoea, excision is the treatment.
Neuroenteric cysts: Develops because of failure of separation ofnotochord form primitive gut. Presents in infants less than 1 year ofage. It is connected to meninges. Possess endodermal or ectodermalneurogenic element. Associated with scoliosis , hemivertebrae, spinabifida. Excision is the treatment of choice.
OTHER MEDIASTINAL TUMORS
• Amyloid masses
• Castleman’s disease
• Chordomas
• Fibromas
• Mesotheliomas
• Rhabdomyosarcomas
• Myxomas
• Hemangiomas
• Lymphangiomas
CLINICAL FEATURES
• 40% are asymptomatic . Detected incidentally by routine chest x-
ray.
• 60% are symptomatic. Symptoms may be due to
§ Compression – cough, dyspnoea, stridor.
§ Invasion – pain, hoarseness, Horner’s syndrome
§ Paraneoplastic syndromes
§ Haemoptysis
• Asymptomatic patients usually present with benign lesions while
assisted thoracoscopic surgery and open surgical procedures.
Percutaneous US-Guided Needle Biopsy:
Ultrasonography is an effective modality for guidance of
percutaneous biopsy. Compared with CT, US-guided biopsy offers a
number of advantages including bedside approach, lower cost, lack of
radiation exposure, and real-time monitoring (7). With real-time
monitoring by means of US guidance, the tip of the biopsy-needle can
be monitored throughout the procedure. Another great advantage of
US-guided biopsy is that it can approach the lesion from any direction.
This advantage allows biopsy of an upper mediastinal lesion via a
supraclavicular approach . CT-guided biopsy of this region is usually
hindered by surrounding bony structures at an axial plane. On the other
hand, the greatest limitation of USguided biopsy is that its clinical
application for thoracic lesions is generally confined to anterior or
posterior mediastinal tumors that are in contact with the chest wall. TheUSG units equipped with Doppler US may be preferable, as DopplerUSG can be used to detect vessels and blood flow that should beavoided from the biopsy root. After confirming the biopsy root, theUSG probe is equipped with a sterile puncture transducer with aguiding channel. If the lesion is less than 20 mm to 22 mm in diameter,the tip of the needle should be placed at least 20 mm away from theposterior margin of the lesion. To reduce the false-negative rate, havinga cytologist present during biopsy has been advocated.
Percutaneous CT-Guided Needle Biopsy
This procedure is performed percutaneously under CT-
fluoroscopic guidance.9 Before the procedure, CT images are obtained
for targeting the lesion. The needle path is determined, avoiding
interlobular fissures, visible bronchi, and relatively large vessels. The
needle path may be through the lung , a route that cannot be used in
US-guided biopsy. After the administration of local anesthesia, the
introducer needle is advanced along the determined path until its tip is
in front of the lesion. Acquisition of a specimen is repeated until the
specimens obtained are considered adequate for histologic evaluation.
Chest CT images are obtained to evaluate procedural complications.
Pneumothorax (8%–61%) is the most commonly encountered
complication after USG guided or CT guided needle biopsy, followed
by hemoptysis (1.6%–3%).
USG-Guided Endoscopic Biopsy
Endobronchial ultrasound , first introduced during the early
1990s, has emerged as a new diagnostic tool that allows visualization
beyond the airway.10 Because of the development of miniaturized
radial probes with flexible catheters having a balloon at the tip (Fig. 6),
bronchoscopists can perform real-time EBUS-guided transbronchial
needle aspiration (EBUS-TBNA). Although EBUSTBNA is mainly
used for lymph node staging in lung cancer, it can also be used for
tissue diagnosis for middle mediastinal lesions. A 22-gauge needle is
passed through the airway wall and inserted into the lesion under real-
time ultrasound control. Esophageal US-guided fine-needle aspiration
needle biopsy is sometimes indicated for the posterior- and inferior-
mediastinal lesions. EBUS-TBNA is minimally invasive and can be
performed quite safely under local anesthesia. The disadvantages are
that the tissue sample is small, the procedure is time-consuming and
technically demanding, and it requires expensive tools. It is for these
reasons that this procedure can be performed only in some centers.
Parasternal Anterior Mediastinotomy
When needle biopsy has failed, many surgeons prefer
Chamberlain’s approach:11 an open biopsy using a parasternal anterior
mediastinotomy. The patient is placed under general anesthesia in a
supine position. Local anesthesia is occasionally used. A 3-cm to 4-cm
transverse parasternal skin incision is made at the desired intercostal
space, depending on the location of the tumor. Great care should be
taken to stay lateral to the internal mammary vessels. Under direct
visualization between the ribs and using biopsy forceps, an adequately
sized specimen can be obtained from an anterior mediastinal tumor.
Para-aortic lesions and masses arising from the aortopulmonary
window can be reached by inserting a mediastinoscope through the
parasternal incision.
Mediastinoscopy
Conventional mediastinoscopy and recently developed video
mediastinoscopy are generally used for evaluating the mediastinal
lymph nodes in patients with carcinoma of the lung. These techniques
are also useful for the diagnosis of mediastinal lesions located in the
pretracheal, paratracheal, and subcarinal spaces.12 Under general
anesthesia, a small transverse incision is made 2 cm above the sternal
notch. The pretracheal fascia is incised and a tunnel created by gentle
finger dissection along the anterior and lateral walls of the trachea in to
the mediastinum. The mediastinoscope is then introduced and advanced
further by means of blunt instrument dissection to extend the
mediastinal tunnel. Great care should be taken to avoid vascular injury
and left-recurrent nerve palsy. An adequately sized tissue sample can be
obtained using biopsy forceps.
Video-Assisted Thoracoscopic Surgery
Video-assisted thoracoscopic surgery (VATS) has been widely
used for various types of thoracic surgery. Under general anesthesia, the
patient is intubated with a double-lumen endotracheal tube and placed
in a lateral decubitus position. With the lung collapsed, the entire
thoracic cavity is visible. VATS is a valuable procedure, especially in
cases of lesions with difficult access that require direct vision, such as
tumors close to great vessels or the heart.13,14 The disadvantage of
VATS biopsy for mediastinal tumor is possible tumor seeding to the
thoracic cavity by opening the pleura.
DECISION-MAKING
One can make a reasonable preoperative diagnosis for each
lesion by considering the age of the patient, location, the presence or
absence of symptoms and signs, the association of a specific systemic
disease, radiographic findings, and biochemical markers. The decision
about how to manage a mediastinal tumor could be made by
observation, surgical resection, chemotherapy, radiotherapy, or
multimodality therapy depending on the nature of the disease. Since the
introduction of VATS, the threshold for surgical resection of the lesion
has been lowered. In most patients with cystic lesions or probable
benign solid tumors, such as neurogenic tumors in adults, VATS
extirpation of the lesion is recommended without biopsy, being both
diagnostic and therapeutic simultaneously. When radiographs show
typical signs of benign germ cell tumors, mature teratomas, or early
stage thymomas, it is recommended for open or VATS resection
without biopsy. It is much more difficult to make a precise diagnosis
for poorly demarcated tumors in the anterior or middle mediastinum.
Approach : R.ALT, L.ALT, MS,L.PLT, R.PLTR.AT, L.AT, MiS
Tumor Location, Size :
Post operative outcome :
Complication : Morbidity, Mortality
Adjuvant Therapy : CT, RT, Plasmapheresis
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