Mediastinal Tumors: Update 1995

132 Pages·1995·5.319 MB·English

by  Johanne LeBlanc M.D., Douglas E. Wood M.D. (auth.), Douglas E. Wood MD, Charles R. Thomas Jr. MD (eds.)

MEDICAL RADIOLOGY
Diagnostic Imaging and Radiation Oncology
Editorial Board
Founding Editors: L.W. Brady, M.W. Donner (t), H.-P. Heilmann,
F.H.W. Heuck
Current Editors: A.L. Baert, Leuven . L.W. Brady, Philadelphia
H.-P. Heilmann, Hamburg . F.H.W. Heuck,
Stuttgart . J.E. Youker, Milwaukee
Mediastinal Tumors
Update 1995
Contributors
M.S. Allen. ID. Bitran . L. Delbridge . B. De Vries . L.P. Faber
R.I Ginsberg . T.W. Griffin . R.F. Heitmiller . S. Keshavjee
W.-J. Koh . J. LeBlanc . R.B. Lee . PJ. Loehrer, Sr.
WJ. Marasco . D.J. Mathisen J.I. Miller, Jr .. S.H. Petersdorf
T.S. Reeve . M. Roach III . J. Somers . C.R. Thomas, Jr.
S. Vijayakumar . IC. Wain . E.W. Wilkins, Jr .. D.E. Wood
C.D. Wright
Edited by
Douglas E. Wood and Charles R. Thomas, Jr.
Foreword by
Luther W. Brady and Hans-Peter Heilmann
With 55 Figures and 21 Tables
Springer-Verlag
Berlin Heidelberg New York
London Paris Tokyo
Hong Kong Barcelona
Budapest
DOUGLAS E. WOOD, MD
Head, Section of General Thoracic Surgery
Division of Cardio-thoracic Surgery
Department of Surgery, SA-25
University of Washington
1959 NE Pacific Street
Seattle, W A 98195
USA
CHARLES R. THOMAS, JR., MD
Fellow, Department of Radiation Oncology, RC-08
Former Assistant Professor, Division of Oncology
Department of Medicine
University of Washington
1959 NE Pacific Street
Seattle, W A 98195
USA .
MEDICAL RADIOLOGY . Diagnostic Imaging and Radiation Oncology
Continuation of
Handbuch der medizinischen Radiologie
Encyclopedia of Medical Radiology
ISBN-13 :978-3-642-79428-5 e-ISBN-13 :978-3-642-79426-1
DOl: 10.1007/978-3-642-79426-1
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Foreword
Primary mediastinal tumors are relatively rare. The relative incidence of these tumors
indicates that neurogenic tumors are the most common tumor seen constituting 21 % of
all cases, thymomas 19%, lymphomas 12.5%, germ cell tumors 10%, primary carcinomas
4.6%, mesenchymal tumors 6%, endocrine tumors 6%, cysts 18%. In adults, the majority
of thyroid tumors, thymomas, mediastinal germ cell tumors and teratomas are located in
the superior and anterior mediastinum. Of the neurogenic tumors 18% are located in the
posterior mediastinum, and 50% of mediastinal lymphomas are in the middle mediastinum.
In adults, the incidence of anterosuperior, middle and posterior mediastinal tumors is about
54%, 20% and 26% respectively. However, in children the posterior mediastinum contains
63% of the lesions, the anterior mediastinum contains 26% and the middle mediastinum
II %. The majority of the tumors are benign in character with a ratio of benign to malig
nant of about 60 to 40. The relative incidence of malignant mediastinal tumors in children
is about 50%.
Even though mediastinal tumors are not common, they represent a unique problem with
regards to treatment whether by surgery, radiation therapy and/or systemically administered
chemotherapy.
The volume by WOOD and THOMAS deals with each of these issues in detail and
presents a logical and important approach to the management of mediastinal tumors.
Philadelphia LUTHER W. BRADY
Hamburg HANS-PETER HEILMANN
January 1995
Preface
Mediastinal tumors present a fascinating and varied array of benign and malignant
neoplasms. Cardiothoracic surgeons, general surgeons, medical and radiation oncologists,
radiologists, pulmonologists, pediatricians, endocrinologists, and pathologists are all in
volved in the diagnosis and management of mediastinal tumors. Due to this wide spec
trum of diseases and specialists, the literature on mediastinal tumors is scattered through
the journals of multiple disciplines. As a result, many physicians do not have a clear
understanding of this diverse array of tumors. In the past few years diagnostic techniques
have improved with serum tumor markers. MR!, and more sophisticated imaging by CT
and ultrasound. At the same time, advances in chemotherapy, radiation, and surgery have
improved the outcomes for tumors that were previously "incurable" and interdisciplinary
cooperation has resulted in many multimodality treatment protocols. This volume is aimed
at consolidating the literature and providing a concise guide and reference to the state
of-the-art diagnosis and management of mediastinal tumors. We have enlisted thoracic
surgeons, medical and radiation oncologists, and radiologists who are experienced in spe
cific mediastinal tumors to provide thorough updates in their area of expertise. We greatly
appreciate their important contributions to the field and to this supplement.
Seattle, W A 98195, USA DOUGLAS E. WOOD
February 1995 CHARLES R. THOMAS, Jr.
Acknowledgement. We wish to give our sincere thanks to TERRI BODEN MAN for all her
help and hard work in preparing this volume. Without her dedication and perseverance
this issue would probably be titled Mediastinal Tumors: Update 1997.
Contents
Diagnosis of Mediastinal Masses
JOHANNE LEBLANC and DOUGLAS E. WOOD
2 Thymoma: Surgical Management
EARLE W. WILKINS, JR. ..................................... 11
3 Thymoma: Radiation and Chemotherapy
WUI-JIN KOH, PATRICK J. LOEHRER, SR., and CHARLES R. THOMAS, JR. 19
4 Mediastinal Lymphomas
STEPHEN H. PETERSDORF 27
5 Benign Mediastinal Germ Cell Tumors
MARK S. ALLEN .......................................... 37
6 Nonseminomatous Germ Cell Tumors of the Mediastinum
CAMERON D. WRIGHT, JOHN C. WAIN and DOUGLAS J. MATHISEN 43
7 Primary Mediastinal Seminoma
RICHARD F. HEITMILLER and WILLIAM J. MARASCO 49
8 Endocrine Tumors of the Mediastinum
THOMAS S. REEVE and LEIGH DELBRIDGE 55
9 Mediastinal Paragangliomas
ROBERT B. LEE and JOSEPH I. MILLER, JR. 63
10 Neurogenic Tumors of the Mediastinum
JOHN C. WAIN ........................................... 71
11 Cardiac Neoplasms
CHARLES R. THOMAS, JR., BRENT DE VRIES, JACOB D. BITRAN and
THOMAS W. GRIFFIN ....................................... 79
12 Tracheal Tumors
DOUGLAS E. WOOD 87
13 Mesenchymal Tumors of the Mediastinum
JONATHAN SOMERS and L. PENFIELD FABER 95
14 Undifferentiated Carcinoma of the Mediastinum
SHAFIQUE KESHAVJEE and ROBERT J. GINSBERG 111
X Contents
15 The Role of Tbree-Dimensional Conformal Radiotherapy
in the Treatment of Mediastinal Tumors
MACK ROACH III and SRINIVASAN VIJAY AKUMAR ................... 117
Subject Index .............................................. 125
List of Contributors .......................................... 129
1 Diagnosis of Mediastinal Masses
JOHANNE LEBLANC and DOUGLAS E. WOOD
CONTENTS posteriorly by the pericardium and great vessels.
It contains the pericardium and the heart, the as
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . I
cending and transverse aorta, the brachiocephalic
1.2 General Diagnostic Features . . . . . . . . . . I
1.3 Diagnostic Studies . . . . . . . . . . . . . . . . . . . . 2 vessels, the pulmonary artery and veins, the infe
1.4 Diagnostic Imaging of Mediastinal Masses rior and superior vena cavae, and the trachea and
in the Adult. . . . . . . . . . . . . . . . . . . . . . . . 2 main bronchi with their contiguous lymph nodes.
1.4.1 Anterior Mediastinum ............... . 2
The posterior mediastinum is bounded anteriorly by
1.4.2 Middle 'Mediastinum .......... . 6
1.4.3 Posterior Mediastinum ............... . 8 the pericardium and posteriorly by the chest wall
1.5 Tissue Diagnosis and Staging. . . . . . . . . . . 8 including the paravertebral gutters. It includes the
1.5.1 Needle Biopsy .................. . 8 esophagus, azygos and hemi-azygos veins, nerves,
1.5.2 Mediastinoscopy
fat and lymph nodes [1].
and Anterior Mediastinotomy. . . . . . . . . . 8
1.5.3 Thorascopy and Thoracotomy . . . . 8 Malignant mediastinal lymph nodes may be pri
1.6 Conclusion ............... . 9 mary or secondary in origin. Mediastinal metastatic
References. . . . . . . . . . . . . . . . 9 neoplasms usually arise from lymphatic spread from
lung, esophageal, breast, thyroid, or gastric primaries
to mediastinal lymph nodes. We will devote our dis
1.1 Introduction
cussion to primary tumors of the mediastinum, and
in this chapter will present the fupdamentals of the
The mediastinum is defined as the space between
workup and diagnosis of mediastinal masses. Sub
the two pleural cavities extending from the thoracic
sequent chapters written by experienced radiologists,
inlet to the diaphragm. It is bounded by the sternum
oncologists, and thoracic surgeons will specifically
anteriorly and the vertebral bodies posteriorly. The
outline the presentation and management of the wide
paravertebral gutters have traditionally been included
variety of mediastinal neoplasms.
when considering mediastinal masses.
The mediastinum can be divided into three or
four compartments and a variety of definitions have
1.2 General Diagnostic Features
been used, adding confusion to the radiologic and
surgical literature. The most commonly used
The incidence and location of primary mediastinal
definition divides the mediastinum into anterior,
tumors in children is clearly different than in adults.
middle, and posterior compartments. The anterior
Collected series have shown that neurogenic tumors
mediastinum is bounded anteriorly by the sternum
and foregut cysts are nearly twice as common in
and posteriorly by the pericardium, brachiocephalic
children with mediastinal masses than in adults and
vessels, and aorta. It contains the thymus gland,
in children make up 39% and 18% of the medi
internal mammary vessels, and lymph nodes. The
astinal masses respectively. Germ cell tumors and
middle mediastinum is b0.mded anteriorly and
1 lymphomas each contribute about 13% in both chil
dren and adults. Thymomas make up 21 % of adult
mediastinal masses but are quite uncommon in chil
JOHANNE LEBLANC, M.D., Clinical Assistant Professor,
dren. Miscellaneous tumors and cysts produce the
University of Washington, Department of Radiology, Group
Health Cooperative of Puget Sound, 215, 15th Ave., Seattle, other 20% in children and adults [2]. Approximately
WA 98102, USA two-thirds of mediastinal tumors are symptomatic
DOUGLAS E. WOOD, M.D., Head, Section of General Tho
in children while only one-third produce symptoms
racic Surgery, Assistant Professor, Division of Cardiothoracic
in adults [3]. Asymptomatic neoplasms are usually
Surgery, SA-25, University of Washington, Seattle, WA
98195. USA found during routine- chest radiographs. Signs and
2 Johanne LeBlanc and Douglas E. Wood
symptoms that do occur result from invasion or com are biochemical markers that should be obtained in
pression of local structures, the presence of infec certain clinical settings. All young men with an
tion, or the release of endocrine products. anterior mediastinal mass should have oc-fetoprotein
Respiratory symptoms often predominate, partic and {3-HCG levels obtained to evaluate the presence
ularly in infants and children, due to compression of a nonseminomatous germ cell tumor. Infants and
of the airway. Involvement of the esophagus may children with a paravertebral mass should have mea
produce dysphagia or odynophagia. Anterior and surement of urinary catecholamines, metanephrines,
middle mediastinal masses may produce superior and vanillylmandelic acid. Other markers have been
vena cava syndrome and invasion into the chest wall useful for following the course of patients during
usually produces pain. Pleural and pericardial effu treatment. Placental alkaline phosphatase has been
sions are possible and a chylothorax can occur from used as a serum marker for patients with seminoma
malignant lymphatic obstruction. Nerve involvement and neuron-specific enolase and chromograffin can
in the middle mediastinum may result in hoarse be used as a marker for bronchial or thymic carci
ness or diaphragmatic paralysis, and in the poste noids [9].
rior mediastinum may result in Homer's syndrome,
upper extremity pain, back pain, or even paraplegia.
Systemic signs of infection may lead to a diagnosis 1.4 Diagnostic Imaging of Mediastinal Masses
of an infected foregut cyst. Other systemic symp in the Adult
toms or signs may be present in both malignant and
benign mediastinal tumors. These will be discussed Assessment of mediastinal abnormalities is a chal
separately in subsequent chapters. lenging task for the radiologist. The majority of
The incidence of malignancy depends on the these masses are found on conventional chest radio
location of the mass, presence of symptoms and the graphs. With the advance of cross-sectional imag
age of the patient. Anterior mediastinal masses are ing, computed tomography (CT) has become the
more commonly malignant (59%) than are middle modality of choice to assess the specific character
mediastinal masses (29%) or posterior mediastinal istic of mediastinal masses or to detect them when
masses (16%) [4]. Asymptomatic patients with a an abnormality is clinically suspected. In selective
mediastinal mass have a benign diagnosis 76% of cases, magnetic resonance imaging (MRl) is helpful
the time while symptomatic patients have a malig due to its multiplanar possibilities to assess involve
nant neoplasm 62% of the time [4]. The incidence ment of surrounding structures not answered by CT
of malignancy in mediastinal masses is greater in scan. It is especially useful for assessing vascular
children than in adults. The most common medi invasion or aneurysms, but also very useful in case
astinal mass in children is a neurogenic tumor with of allergy to iodinated contrast agents. Ultrasonog
an incidence of malignancy ranging from 60% to raphy is useful in some mediastinal masses, espe
85% [5,6], while the incidence of malignancy is cially anterior masses, either to characterize a lesion
only 10/0-3% for neurogenic tumors in adults [7]. as cystic or solid or to guide percutaneous biopsy.
DAVIS and colleagues [8] found a lower incidence of Radionuclide scanning plays an important role pre
malignancy in patients 10 years of age and younger, dominantly in the assessment of thyroid and para
compared to the incidence of malignancy from the thyroid lesions.
second to the fourth decades of life. Definition of the specific compartment in which
the lesion is found and its radiologic characteristics
are very helpful in narrowing down the differential
1.3 Diagnostic Studies diagnosis of the lesion involving the mediastinum.
Mediastinal masses noted on chest radiograph can
be narrowed down to a limited differential diagnosis 1.4.1 Anterior Mediastinum
based upon the patient's age, presence of symptoms,
and location. All patients should undergo a thorough 1.4.1.1 Thyroid
history and physical examination eliciting symptoms
and signs of direct or indirect tumor invasion or Substernal thyroid goiter is a common lesion arising
involvement, as well as systemic signs of disease. from the cervical region in the superior and anterior
Routine laboratory studies will add little to the mediastinum. It may even extend below the carina.
diagnosis of most mediastinal masses, but there Rarely, true ectopic thyroid tissue can be found in
Diagnosis of Mediastinal Masses 3
the mediastinum [10]. On plain film, it often presents may encase the trachea, causing narrowmg of the
as an asymptomatic para tracheal soft tissue mass that airway. Though other symptoms such as superior
may contain calcifications and sometimes displaces vena cava obstruction may occur, true superior vena
the trachea laterally and occasionally anteriorly due cava syndrome is rare in the absence of malignancy
to a retrotracheal component (Fig. 1.1). [10].
Computed tomography provides excellent infor Differentiating between benign and malignant
mation in the assessment of the substernal goiter. lesions of the thyroid gland is usually not possi
Enlargement tends to arise from the inferior pole ble with imaging techniques. Irregular borders of the
of a thyroid lobe and the mediastinal mass usually mass with or without invasion of the surrounding
has a clear continuity with the often enlarged cer fat planes, presence of enlarged lymph nodes, and
vical thyroid. Substernal goiters have well-defined invasion of surrounding structures are all character
borders and often contain calcifications that are istics suggesting malignancy [13, 14]. MRI seldom
coarse or ring-like. They are heterogeneous, with adds additional information unless it is used to help
areas of low density [11, 12]. Thyroid tissue is determine vascular involvement.
dense before contrast injection and enhanced after Thyroid scintigraphy is extremely helpful and
injection of iodinated contrast agent. The enlarged readily available to provide diagnostic information
thyroid tenqs to insinuate into the mediastinum by regarding an anterior mediastinal mass suspected
displacing the great vessels laterally but sometimes to be an enlarged thyroid. In these cases, the nu
clear scan will most often show an enlarged thyroid
gland protruding in the upper mediastinum with
multiple hot and cold nodules. It also has the advan
tage of providing information concerning the thyroid
function.
1.4.1.2 Parathyroid
Four parathyroid glands are usually found in the
cervical region. They can be supernumerary and
ectopic. It is unusual to have a parathyroid adenoma
presenting as a mediastinal mass. More commonly,
patients will be diagnosed with primary hyperpara
thyroidism and a search made for the abnormal
a
gland or glands.
Preoperative imaging in cases of primary hyper
parathyroidism is often considered optional by the
surgeon, but is mandatory in cases of persistent or
recurrent hyperparathyroidism after cervical explo
ration. Ultrasound is considered the most valuable
modality for the assessment of the cervical region.
Real-time ultrasound will reveal the abnormal para
thyroid as a small round well-defined hypoechoic
mass.
Persistent hyperparathyroidism after surgery, how
ever, is often due to an ectopic parathyroid gland.
Eighty percent of ectopic parathyroids are located
in the anterior mediastinum within or adjacent to
b the thymus at the level of the innominate vessels
[10]. Ultrasound has a limited value when the
Fig. 1.1a, b. Intrathoracic goiter. a Chest radiograph demon ectopic lesion is in the mediastinum, where thallium
strating a large left paratracheal mass displacing the trachea
technetium subtraction scintigraphy and CT have
to the right. b Enhanced CT scan showing a large hetero
proven useful. CT is performed with IV contrast and
geneous mass with well-defined borders displacing the tra
chea to the right and the brachiocephalic vessels laterally is most accurate with lesions measuring more than