Cancer Prognostics and Diagnostics
Review Article
Imaging of Pedeatric Madiastinum
Kakarla Subbarao1*
1
Department of radiology and imaging, KIMS, Secunderabad, India.
Copyright: © 2016 Kakarla Subbarao. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Abstract
This is a review article on imaging findings in mediastinal pathology. Mediastinum is better studied on imaging methods such as plain radiography, MDCT, MRI and
angiography. The characteristic findings of various mediastinal masses are described with a stress on plain radiography. Preoperative diagnosis can be made with imaging.
Key words: Pediatrics, mediastinal masses, plain radiography
• Thymus
Introduction
• Thyroid
Mediastinum is a median septum or partition containing mass
of tissues and organs between the two pleural sacs. Anteriorly the
sternum, posteriorly vertebral column, superiorly thoracic inlet and
inferiorly diaphragm constitute its borders. Heart is considered to
be in the anterior mediastinum. Aortic arch, descending aorta and
pulmonary vessels are in the middle mediastinum. These structures
can be identified in posteroanterior and lateral chest radiographs and
abnormal masses can be studied123. CT and MRI may help to study
the matrix as well as the capsule, thus, giving a histological diagnosis4.
FNAC / biopsy are conducted to confirm the diagnosis.
• Teratoma
The imaging methods are in the following table Table I: Plain
radiography of the chest – PA and lateral, MD CT
MRI, Angiography, Pet CT
In children, ALARA principle, (as low as reasonably allowable)
should be adopted so that minimal radiation is used as the children
are very sensitive to radiation exposures.
Mediastinum is divided into various compartments (Figure 1ab).
Felson [1] and other authors have divided the mediastinum into
various compartments and Felson’s method is followed in this study2.
The following table lists the anterior mediastinal masses in
children (Table II)
Table II: Enlarged thymus, Cystic Hygroma, Lymphoma,
Teratodermoid
Thymomas are not generally encountered in children
In pediatric practice, most common mediastinal mass is the
enlarged thymus. This may persist up to 4 years and rarely encountered
even at 6-8 years [2]. Spontaneous regression is known and steroid
therapy may help when the child is having respiratory problems
(Figure 2ab). Radiologically, several signs have been described
including the sail like density in the paratracheal area (Figure 3ab).
A wavy sign has been described where the costal cartilages
produce an impression on the thymus (Figure 4ab-8abc).
The common anterior mediastinal masses, generally go by the
eponem (4Ts)
Cancer Prog Diagn, 2016
• Terrible lymphoma
The masses in the middle mediastinum are listed in the table III:
Lymph nodes, Bronchogenic cyst, Vascular Esophageal, Hernia
The most common middle mediastinal mass is due to enlarged
lymph nodes
The etiologies are listed in table IV: Tuberculosis, Sarcoid,
Lymphoma, Leukemia, Infectious mononucleosis, Pseudo lymphoma,
Castleman’s disease, Angio immuno lymphadenopathy Figure 9
CT imaging is performed to find out various sites of
lymphadenopathy
Figure 10ab, Figure 11abc Next entity is sarcoidosis. Although,
sarcoidosis is not very common in India and yet several cases have
been reported in all ages [3]. Right paratracheal and bilateral hilar
lymphadenopathy is characteristic. Unilateral hilar adenopathy may
also be encountered [4]. Figure 12
Vascular rings and slings
These are often produce mediastinal widening simulating masses.
Of these, right sided aorta with or without associated congenital heart
disease is common. Although, plain films are classical as there is no
normal aortic shadow on the left and an abnormal shadow is seen on
right side of the trachea [5]. Normally, the trachea is deviated to the
right by the presence of aortic knob. In right side aorta5, the trachea
is deviated to the left (Figure 13a). Esophagogram confirms the nature
of the aorta. Angiogram is rarely necessary except when congenital
heart disease is suspected (Figure 13bc). Multidetector CT Angiogram
is the latest investigation to be performed to study the cardiovascular
structures (Figure 14ab)
*Corresponding author: Kakarla Subbarao, Department of radiology and
imaging, KIMS, Secunderabad, India, Tel: ; Fax: ; E-mail: subbaraokakarla25@
gmail.com
Received: October 06, 2016; Accepted: October 31, 2016; Published:
November 09, 2016
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Citation: Kakarla Subbarao (2016) Imaging of Pedeatric Madiastinum. Cancer Prog Diagn 1: 104
Old classification
Felson’s Classification
a
b
Figure 1ab: a. Mediastinal compartments, b. A-Anterior, M- middle and P-posterior.
a
b
Figure 2ab: a- Persistent thymus, b-Post steroid therapy.
a
b
Figure 3ab: a-Enlarged thymus, b-Sail like sign.
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a
b
Figure 4ab: a-Enlarged thymus – wavy sign, b-Compression by costal cartilages anteriorly.
a
b
Figure 5ab: Teratodermoid - Note Calcification in the anterior mass.
a
b
Figure 6ab: Large anterior mediastial mass due to lymphoma.
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a
b
Figure 7ab: a-Lymphoma, b- 2 Months later with effusion.
a
b
c
Figure 8abc: ab- Right anterior mediastinal mass due to lymphoma, c- osteoarthropathy of the lower limbs.
Figure 9: Tuberculous lymphadenopathy.
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Citation: Kakarla Subbarao (2016) Imaging of Pedeatric Madiastinum. Cancer Prog Diagn 1: 104
a
b
Figure 10ab: Hodgkin’s lymphadenopathy, b-CT right paratracheal and para-aortic adenopathy.
a
b
c
Figure 11abc: Lymphoma at various stages
Figure 12: 16 yr old - Sarcoidosis with hilar lymphadenopathy.
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Figure 13a: Right sided aorta.
b
c
Figure 13bc: Esophagogram with right sided aorta.
a
b
Figure 14ab: a-Esophagogram, b-CT angiogram - Right sided aorta.
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Citation: Kakarla Subbarao (2016) Imaging of Pedeatric Madiastinum. Cancer Prog Diagn 1: 104
a
b
Figure 15ab: Esophgeal duplication cyst.
Figure 15c: CT showing fluid in the cyst.
Figure 16a: 6 yr M – Neuroblastoma.
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b
c
Figure 16bc: CT neuroblastoma showing calcifications.
a
b
c
Figure 17abc: a-AP, b-Lateral, c-Esophagogram – Neuroblastoma with calcifications.
Figure 17d: CT necrotic centre in neuroblastoma.
Figure 17d: CT necrotic centre in neuroblastoma.
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Citation: Kakarla Subbarao (2016) Imaging of Pedeatric Madiastinum. Cancer Prog Diagn 1: 104
b
c
d
Figure 18bcd: CT angiogram ganglioneuroma.
Next entity in the middle mediastinum comprises duplication
cysts. Duplication cysts are congenital in nature and they may present
as solid lesion on radiography (Figure 15ab). If they communicate
with the respiratory / esophagus tract6. They may contain fluid / air
[6]. CT often helps in identifying the nature of contents (Figure. 15c)
Observe alarp principle as far as possible to avoid radiation exposure
in children [7]. CT of the chest is often avoided and replaced by
ultrasonography or magnetic resonance imaging. The indications are
mentioned in table V
Table V - Indications for CT Chest
Table V: Identify mediastinal mass, To differentiate between solid
and cystic lesions, To identify calcification, To identify fat, To study
cardiovascular system
Summary
Mediastinal Lesions in children are ideally studied by conventional
radiographs. Where ever indicated advanced imaging methods are
adopted. CT is minimally used to avoid excesive radiation. As far as
possible ultrasonography and MRI studies should be replaced in the
place of CT. Divisions of mediastinum help in identifying various
masses.
References
1. Felson B (1968) More chest roentgen signs and how to teach them. Annual
Oration in memory of L. Henry Garland MD 1903-1966. Radiology 90: 429441. [crossref]
2. Felson B (1969) The mediastinum. Semin Roentgenol 4:41-58.
3. Han BK, Babcock DS, Oestreich AE (1989) Normal thymus in infancy:
sonographic characteristics. Radiology 170: 471-474. [crossref]
Most of the posterior Mediastinal masses are neurogenic and
include the following:
4. Brown LR, Aughenbaugh GL (1991) Masses of the anterior mediastinum: CT
and MR imaging. AJR Am J Roentgenol 157: 1171-1180. [crossref]
Table VI - Neurogenic Masses
5. Kuhlman JE, Fishman EK, Wang KP, Zerhouni EA, Siegelman SS, et al.
(1988) Mediastinal cysts: diagnosis by CT and needle aspiration. AJR Am J
Roentgenol 150: 75-78. [crossref]
Table VI: Neuroblastoma, Ganglioneuroma, Neurofibroma,
Neurenteric cyst, Meningocele (Intrathoracic) Figure 16abc,
Figure 17abc Neuroblastoma constitutes 75% of neurogenic
tumors78. Next in order include ganlionic origin, ganglioneuroma,
ganglioneuroblastoma [8]. Neurofibromas and schwannomas are
uncommon in children. Figure 17 d The other masses include the
following: Lymphoma, Extramedullary hemopoiesis mass, Hernia,
Ectopic kidney Figure 18
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6. Predey TA, McDonald V, Demos TC, Moncada R (1989) CT of congenital
anomalies of the aortic arch. Semin Roentgenol 24: 96-113. [crossref]
7. Padovani B, Hofman P, Chanalet S, Taillan B, Jourdan J, et al. (1992)
Intrapericardial bronchogenic cyst: CT and MR demonstration. Eur J Radiol 15:
4-6. [crossref]
8. Sakai F, Sone S, Kiyono K, Maruyama A, Ueda H, et al. (1992) Intrathoracic
neurogenic tumors: MR-pathologic correlation. AJR Am J Roentgenol 159: 279283. [crossref]
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