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{{Mediastinal mass}}
{{Mediastinal mass}}


{{CMG}}; {{AE}} {{Trusha}}, {{AM}}
{{CMG}}; {{AE}}{{Trusha}}


{{SK}} Mediastinal enlargement; mass in the mediastinum
{{SK}} Mediastinal enlargement; mass in the mediastinum


==Overview==
==Overview==
The [[mediastinum]] is a non-delineated group of structures in the thorax (chest), surrounded by loose connective tissue. It is the central compartment of the thoracic cavity. It contains the heart, the great vessels of the heart, esophagus, trachea, thymus, and lymph nodes of the central chest. A wide variety of diseases involving these organs can present as a mediastinal mass or widening of the mediastinum on imaging studies. Mediastinal widening is diagnosed by the mediastinum measuring greater than 8 cm in width on PA chest x-ray. The mediastinal mass may present with symptoms caused by the mass pressing against other organs or even without any symptoms. Mediastinal masses can be differentiated on the basis of location in the mediastinal cavity into 3 groups: Prevascular, visceral and paravertebral.
The [[mediastinum]] is a non-delineated group of structures in the [[Thorax|thorax (chest)]], surrounded by [[loose connective tissue]]. It is the central [[Compartment (anatomy)|compartment]] of the [[thoracic cavity]]. The [[mediastinum]] lies between the [[Visceral pleura|right and left pleura]] in and near the [[Anatomical terms of location|median sagittal plane]] of the [[chest]]. It extends from the [[sternum]] in front to the [[vertebral column]] behind, and contains all the [[Chest|thoracic]] [[viscera]] except the [[lungs]]. On the basis of [[Computed tomography|cross-sectional imaging]], [[mediastinum]] can be divided into 3 groups: 1) [[Anterior mediastinum|Prevascular compartment:]] which contains [[thymus]], [[fat]], [[Lymph node|lymph nodes]] and [[Brachiocephalic vein|left brachiocephalic vein]]. 2) [[Middle mediastinum|Visceral compartment]], which contains [[trachea]], [[Carina of trachea|carina]], [[esophagus]], [[Lymph node|lymph nodes]], [[heart]], [[Ascending aorta|ascending thoracic aorta]], [[aortic arch]], [[Descending aorta|descending thoracic aorta,]] [[superior vena cava]], [[Pulmonary arteries|intrapericardial pulmonary arteries]], and [[thoracic duct]]. and 3) [[Posterior mediastinum|Paravertebral compartment:]] which contains the [[Thoracic vertebrae|thoracic spine]] and paravertebral tissue. A wide variety of [[Mediastinal mass causes|diseases]] involving these [[Organ (anatomy)|organs]] can present as a mediastinal mass or widening of the [[mediastinum]] on [[imaging studies]]. Mediastinal widening is [[Diagnosis|diagnosed]] by the [[mediastinum]] measuring greater than 8 cm in width on [[Chest x-ray|PA chest x-ray]]. The mediastinal mass may present with [[Symptom|symptoms]] or even without any [[Symptom|symptoms]]. A mediastinal mass may cause a variety of [[Symptom|symptoms]] by the [[Tumor|mass]] pressing against other [[Mediastinum|mediastinal structures]], collectively known as mediastinal syndrome. Mediastinal mass can be differentiated according to the content of the mass such as [[Cyst|cystic mass]], [[Fat|fatty mass]] or [[Neoplasm|solid (tumor)]]. Depending on location and composition of the [[Tumor|mass]] further [[diagnosis]] is made by specific [[imaging studies]], [[Endoscopy|endoscopic studies]], [[Biopsy|tissue biopsies]], [[Histopathology|histopathological studies]] and/or growth of [[microorganism]] on specific [[Growth medium|culture medium]].


==Anatomy of mediastinum==
* The [[mediastinum]] lies between the [[Visceral pleura|right and left pleura]] in and near the [[Anatomical terms of location|median sagittal plane]] of the [[chest]].


* It extends from the [[sternum]] in front to the [[vertebral column]] behind, and contains all the [[Chest|thoracic]] [[viscera]] except the [[lungs]]. It may be divided for purposes of description into two parts:
** '''Superior mediastinum:''' Above the upper level of the [[pericardium]], which is named the [[superior mediastinum]] with its [[superior]] limit at the [[Superior thoracic aperture|superior thoracic opening]] and its [[Anatomical terms of location|inferior]] limit at the plane from the [[sternal angle]] to the [[Thoracic vertebrae|disc of T4-T5]] (plane of Ludwig)
** '''Inferior mediastinum''': Below the upper level of the [[pericardium]]. This lower portion is again subdivided into three parts:
*** In front of the pericardium, the [[anterior mediastinum]]
*** Containing the pericardium and its contents, the [[middle mediastinum]]
*** Behind the pericardium, the [[posterior mediastinum]]
*** It is surrounded by the [[Thoracic cavity|chest wall]] [[Anatomical terms of location|anteriorly]], the [[Lung|lungs]] [[Lateral|laterally]] and the [[Vertebral column|spine]] [[Anatomical terms of location|posteriorly]].
*** It is continuous with the [[loose connective tissue]] of the [[neck]], and extends [[Anatomical terms of location|inferiorly]] into the [[Diaphragm (anatomy)|diaphragm]].


* Note that clinical radiologists and anatomists categorize the mediastinum in slightly different ways.
* The International Thymic Malignancy Interest Group (ITMIG) has developed a new scheme to divide [[Mediastinum|mediastinal cavity]] on the basis of [[Computed tomography|cross sectional imaging]] for better [[Diagnosis|diagnostic]] and [[Therapy|therapeutic]] purposes.<ref name="CarterBenveniste2017">{{cite journal|last1=Carter|first1=Brett W.|last2=Benveniste|first2=Marcelo F.|last3=Madan|first3=Rachna|last4=Godoy|first4=Myrna C.|last5=de Groot|first5=Patricia M.|last6=Truong|first6=Mylene T.|last7=Rosado-de-Christenson|first7=Melissa L.|last8=Marom|first8=Edith M.|title=ITMIG Classification of Mediastinal Compartments and Multidisciplinary Approach to Mediastinal Masses|journal=RadioGraphics|volume=37|issue=2|year=2017|pages=413–436|issn=0271-5333|doi=10.1148/rg.2017160095}}</ref>
** [[Anterior mediastinum|Prevascular (anterior)]]
** [[Middle mediastinum|Visceral (middle)]]
** [[Posterior mediastinum|Paravertebral (posterior)]]
{|
! colspan="3" style="background:#4479BA; color: #FFFFFF;" align="center" + |'''<big>International Thymic Malignancy Interest Group (ITMIG) Classification of Mediastinum</big>'''
|-
! style="background: #4479BA; color: #FFFFFF; text-align: center;" |'''Compartments'''
! style="background: #4479BA; color: #FFFFFF; text-align: center;" |'''Boundaries'''
! style="background: #4479BA; color: #FFFFFF; text-align: center;" |'''Components'''
|-
| style="background: #DCDCDC; padding: 5px; text-align: center;" |'''Prevascular'''
| style="background: #F5F5F5; padding: 5px;" |
* '''Superior:''' [[Superior thoracic aperture|Thoracic inlet]]
* '''Inferior:''' [[Thoracic diaphragm|Diaphragm]]
* '''Anterior:''' [[Sternum]]
* '''Posterior:''' [[Anatomical terms of location|Anterior]] aspect of the [[pericardium]]
* '''Lateral:''' [[Parietal pleura|Parietal mediastinal pleura]]
| style="background: #F5F5F5; padding: 5px;" |
* [[Thymus]]
* [[Fat]]
* [[Lymph node|Lymph nodes]]
* [[Brachiocephalic vein|Left brachiocephalic vein]]
|-
| style="background: #DCDCDC; padding: 5px; text-align: center;" |'''Visceral'''
| style="background: #F5F5F5; padding: 5px;" |
* '''Superior:''' [[Superior thoracic aperture|Thoracic inlet]]
* '''Inferior:''' [[Thoracic diaphragm|Diaphragm]]
* '''Anterior:''' [[Anatomical terms of location|Posterior]] boundaries of the [[Anterior mediastinum|prevascular compartment]]
* '''Posterior:''' [[Vertical direction|Vertical]] line connecting a point on each [[Thoracic vertebrae|thoracic]] [[Body of vertebra|vertebral body]] 1 cm [[Anatomical terms of location|posterior]] to its origin
| style="background: #F5F5F5; padding: 5px;" |'''Non vascular:'''
* [[Trachea]]
* [[Carina of trachea|Carina]]
* [[Esophagus]]
* [[Lymph node|Lymph nodes]]
'''Vascular:'''
* [[Heart]]
* [[Ascending aorta|Ascending thoracic aorta]]
* [[Aortic arch]]
* [[Descending aorta|Descending thoracic aorta]]
* [[Superior vena cava]]
* [[Pulmonary arteries|Intrapericardial pulmonary arteries]]
* [[Thoracic duct]]
*
|-
| style="background: #DCDCDC; padding: 5px; text-align: center;" |'''Paravertebral'''
| style="background: #F5F5F5; padding: 5px;" |
* '''Superior:''' [[Superior thoracic aperture|Thoracic inlet]]
* '''Inferior:''' [[Thoracic diaphragm|Diaphragm]]
* '''Anterior:''' [[Anatomical terms of location|Posterior]] boundaries of the [[Middle mediastinum|visceral compartment]]
* '''Posterolateral:''' Vertical line against the [[Anatomical terms of location|posterior]] margin of the [[Thoracic cavity|chest wall]] at the [[lateral]] margin of the [[Transverse processes|transverse process]] of the [[Thoracic vertebrae|thoracic spine]]
| style="background: #F5F5F5; padding: 5px;" |
* [[Thoracic vertebrae|Thoracic spine]]
* [[Prevertebral muscles|Paravertebral soft tissues]]
|-
| colspan="3" style="background:#DCDCDC;" align="left" + |<small>'''Adapted from [https://doi.org/10.1148/rg.2017160095 Radiographics]'''</small>
|}


==References==
==References==

Latest revision as of 16:43, 12 March 2019

Mediastinal mass Microchapters

Home

Overview

Anatomy of Mediastinum

Causes

Differentiating Mediastinal Mass from other Diseases

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Trusha Tank, M.D.[2]

Synonyms and keywords: Mediastinal enlargement; mass in the mediastinum

Overview

The mediastinum is a non-delineated group of structures in the thorax (chest), surrounded by loose connective tissue. It is the central compartment of the thoracic cavity. The mediastinum lies between the right and left pleura in and near the median sagittal plane of the chest. It extends from the sternum in front to the vertebral column behind, and contains all the thoracic viscera except the lungs. On the basis of cross-sectional imaging, mediastinum can be divided into 3 groups: 1) Prevascular compartment: which contains thymus, fat, lymph nodes and left brachiocephalic vein. 2) Visceral compartment, which contains trachea, carina, esophagus, lymph nodes, heart, ascending thoracic aorta, aortic arch, descending thoracic aorta, superior vena cava, intrapericardial pulmonary arteries, and thoracic duct. and 3) Paravertebral compartment: which contains the thoracic spine and paravertebral tissue. A wide variety of diseases involving these organs can present as a mediastinal mass or widening of the mediastinum on imaging studies. Mediastinal widening is diagnosed by the mediastinum measuring greater than 8 cm in width on PA chest x-ray. The mediastinal mass may present with symptoms or even without any symptoms. A mediastinal mass may cause a variety of symptoms by the mass pressing against other mediastinal structures, collectively known as mediastinal syndrome. Mediastinal mass can be differentiated according to the content of the mass such as cystic mass, fatty mass or solid (tumor). Depending on location and composition of the mass further diagnosis is made by specific imaging studies, endoscopic studies, tissue biopsies, histopathological studies and/or growth of microorganism on specific culture medium.

Anatomy of mediastinum

  • Note that clinical radiologists and anatomists categorize the mediastinum in slightly different ways.
International Thymic Malignancy Interest Group (ITMIG) Classification of Mediastinum
Compartments Boundaries Components
Prevascular
Visceral Non vascular:

Vascular:

Paravertebral
Adapted from Radiographics

References

  1. Carter, Brett W.; Benveniste, Marcelo F.; Madan, Rachna; Godoy, Myrna C.; de Groot, Patricia M.; Truong, Mylene T.; Rosado-de-Christenson, Melissa L.; Marom, Edith M. (2017). "ITMIG Classification of Mediastinal Compartments and Multidisciplinary Approach to Mediastinal Masses". RadioGraphics. 37 (2): 413–436. doi:10.1148/rg.2017160095. ISSN 0271-5333.