MEDIASTINAL BRONCHOGENIC CYSTS OF

ADULTS: Report of 5 cases

A. Fouad, R. Saouab, D. Essaoufi, B. Radouane, S. Chaouir, T. Amil, A. Hanine, J. El Fenni Military Teaching Hospital MV Rabat - Morocco

CH2

INTRODUCTIONINTRODUCTION Bronchogenic cysts are one of the most common Bronchogenic cysts are one of the most common

bronchopulmonary malformations.bronchopulmonary malformations.

Modern imaging techniques such as CT and MRI are Modern imaging techniques such as CT and MRI are

useful for precise preoperative diagnosisuseful for precise preoperative diagnosis..

However, despite advances in diagnostic imaging, the However, despite advances in diagnostic imaging, the

definitive diagnosis of a mediastinal bronchogenic cyst definitive diagnosis of a mediastinal bronchogenic cyst

is histologicalis histological..

The aim of our study is to:

Recall the etiopathogenesis, epidemiological Recall the etiopathogenesis, epidemiological

and clinical data of mediastinal bronchogenic and clinical data of mediastinal bronchogenic

cystscysts

Illustrate the imaging appearance in different Illustrate the imaging appearance in different

modalities of exploration modalities of exploration

MATERIALS AND METHODSMATERIALS AND METHODS

Retrospective study of 5 cases of mediastinal bronchogenic Retrospective study of 5 cases of mediastinal bronchogenic

cysts in adults explored in our service over a period of 9 years. cysts in adults explored in our service over a period of 9 years.

Chest radiography and chest CT were performed in all cases; Chest radiography and chest CT were performed in all cases;

MRI was realised in only one case. MRI was realised in only one case.

Surgical resection was performed in all patients.Surgical resection was performed in all patients.

Histopathological study confirmed the diagnosisHistopathological study confirmed the diagnosis

RESULTSRESULTS

We found in our series 4 women and 1 man with an average age of We found in our series 4 women and 1 man with an average age of

50 years. 50 years.

No pathologic historyNo pathologic history

The The cystcyst was discovered incidentallywas discovered incidentally in 3 cases on the  in 3 cases on the chest chest

radiographyradiography; by ; by dyspneadyspnea in one case and a in one case and a chronic cough in other chronic cough in other

casecase..

The cyst was located in the middle mediastinum in 4 cases and in The cyst was located in the middle mediastinum in 4 cases and in

the anterior mediastinum in 1case. the anterior mediastinum in 1case.

The mean diameter of the cyst was 6.7 cm.The mean diameter of the cyst was 6.7 cm.

Pathological examination of the surgical Pathological examination of the surgical

specimen led to the diagnosis in all cases.specimen led to the diagnosis in all cases.

The postoperative course was unremarkable.The postoperative course was unremarkable.

The subsequent evolution was favorable The subsequent evolution was favorable

RESULTSRESULTS

Case n° 1

Posterior anterior and lateral chest x-ray: infero-lateral opacity of the middle and inferior mediastinum

Contrast material-enhanced CT scan :

a well-circumscribed cyst in contact with the inferior vena

cava

Case n° 2

Chest radiograph:homogeneous  anteriorright mediastinal mass

Axial contrast-enhanced chest CT scan(mediastinal window settings):

a well-circumscribed homogenus cyst In the right latero-tracheal lodge

Axial T1 and T2-weighted MR images shows that the lesion is of similar signal intensity to that of CSF, which suggests a cyst.

Case n° 3

Chest radiograph:homogeneous 

retrocardiac mass

Axial contrast-enhanced chest CT scan (mediastinal window settings) : a well-circumscribed left cyst

in the middle and posterior mediastinum

Case n° 4

Chest radiograph:homogeneous right middle mediastinal

mass

Axial contrast-enhanced chest CT scan (mediastinal window settings) :

a well-circumscribed cyst in the middle mediastinum

Case n° 5

chest radiograph:homogeneous right

paracardiac mass withpleural effusion

Axial contrast-enhanced chest CT scan (mediastinal window settings):

a well-circumscribed hyper dense cyst in the middle mediastinum extended to posterior

mediastinum,with pleural effusion.

DISCUSSION DISCUSSION

Embryological recall

Bronchogenic cysts result from abnormal budding of the ventral Bronchogenic cysts result from abnormal budding of the ventral

foregut that occurs foregut that occurs between the 26th and 40th days of gestation..

They are lined with pseudostratified columnar respiratory They are lined with pseudostratified columnar respiratory

epithelium, and their walls usually contain cartilage, smooth muscle, epithelium, and their walls usually contain cartilage, smooth muscle,

and mucous gland tissue(1). and mucous gland tissue(1).

They may be filled with clear, serous fluid or thick, mucoid They may be filled with clear, serous fluid or thick, mucoid

material. material.

They may occur in any part of the mediastinum, but most are They may occur in any part of the mediastinum, but most are near the

tracheal carina in the middle or posterior mediastinum. .

Mediastinal bronchogenic cysts are sometimes associated with Mediastinal bronchogenic cysts are sometimes associated with other

congenital pulmonary malformations such as sequestration and lobar such as sequestration and lobar

emphysema(2). emphysema(2).

They may undergo an abrupt increase in size as a result of hemorrhageThey may undergo an abrupt increase in size as a result of hemorrhage

or infectionor infection

Epidemiology

Clinical data

The majority are asymptomatic, but they may

occasionally cause symptoms secondary to

compression of adjacent structures.

These symptoms include chest pain, cough, dyspnea,

fever, and purulent sputum(3).

1. Chest radiographs:

It is usually adequate for It is usually adequate for detectingdetecting larger

mediastinal masses as a homogeneoushomogeneous opacityopacity ; ;

But, it is But, it is limited in the tissue characterizationlimited in the tissue characterization of the of the

lesionlesion

  

Imaging findings

 2. CT scan:

It is used to It is used to characterize the mass and clarify its and clarify its

relationship to adjacent mediastinal structures.

It is characteristic when the lesion demonstrates a It is characteristic when the lesion demonstrates a

homogeneous fluid attenuation mass with with a thin or

imperceptible wall. .

Imaging findings

 2. CT scan:

The attenuation value is dependent on The attenuation value is dependent on the contents of the cyst.the contents of the cyst.

It can vary from It can vary from water attenuation to to soft-tissue attenuation. .

The value can be The value can be more than 100 HU owing to a high protein level or owing to a high protein level or

calcium oxalate in the mucoid cyst(4,5). calcium oxalate in the mucoid cyst(4,5).

Air within the cyst is uncommon and suggestive of is uncommon and suggestive of secondary secondary

infectioninfection and communication with the tracheobronchial tree. and communication with the tracheobronchial tree.

CalcificationCalcification occurs occasionally in the wall or within the cyst occurs occasionally in the wall or within the cyst

contents.contents.

Imaging findings!

Imaging findings 3. MRI:

It is helpful in cases where the cystic nature of the

mass is not apparent on CT.

MRI should always be indicated in cases of posterior

mediastinal mass to assess the relationship with the

spine

Imaging findings 3. MRI:

The cystic nature of the mass is confirmed by the high signal

intensity on T2-weighted images regardless of the cyst

contents.

At T1-weightedAt T1-weighted images, images, variable patterns variable patterns of signal intensity are of signal intensity are

seen because of variable cyst contents and the presence of seen because of variable cyst contents and the presence of

protein, hemorrhage, or mucoid material(6). protein, hemorrhage, or mucoid material(6).

A A fluid-fluid level within the bronchogenic cyst may be seen(7). within the bronchogenic cyst may be seen(7).

Differential diagnosis It arises with It arises with other cystic lesions of the mediastinumother cystic lesions of the mediastinum including : including :

Congenital benign cysts : duplication cysts, neurenteric cysts, duplication cysts, neurenteric cysts,

meningocele, pericardial cysts, thymic cysts, cystic teratoma, meningocele, pericardial cysts, thymic cysts, cystic teratoma,

and lymphangioma.and lymphangioma.

Mediastinal abscess

Pancreatic pseudocyst

Clinical history, anatomic position, associated abnormalities

and imaging semiology allow correct diagnosis in many

cases.

The choice of treatment is controversial. The choice of treatment is controversial.

Some authors advocate Some authors advocate surgical excision of all cysts given of all cysts given

their tendency to become infected or rarely, to undergo their tendency to become infected or rarely, to undergo

malignant transformation(8).malignant transformation(8).

Increasingly, these lesions are treated with Increasingly, these lesions are treated with transbronchial or

percutaneous aspiration under CT guidance to both confirm to both confirm

the diagnosis and to treat them. the diagnosis and to treat them.

Small lesions can be Small lesions can be followedfollowed. .

Treatment

Intraoperative appearance of bronchogenic cyst

Intraoperative aspiration of bronchogenic cyst.

CONCLUSIONCONCLUSION A A cystic mediastinal mass with with a thin or

imperceptible wall in a in a subcarinal location should should

be a be a bronchogenic cystbronchogenic cyst..

In cases where the cystic nature is not apparent on In cases where the cystic nature is not apparent on

CT, CT, the high signal intensity on T2-weighted

images should confirm the cystic nature.images should confirm the cystic nature.

REFERENCESREFERENCES 1:LF Rogers, Osmer JC . kyste bronchogénique: un examen de 46 cas Am J Roentgenol

Radium Ther Nucl Med 1964 ; 91 : 273 -283. 2:Groskin SA Embryologie du poumon et des anomalies pulmonaires d'origine du

développement. Dans:. Groskin SA, eds Heitzman c'est le poumon: radiologique-pathologiques des corrélations. 3e éd. St Louis, Mo: Mosby, 1993 ; 13 -42

3:St-Georges R, J Deslauriers, Duranceau A, et al. spectre clinique des kystes bronchiques du médiastin et du poumon chez les adultes. Ann Surg Thorac 1991 ; 52 : 6 -13.

4:Mendelson DS, Rose JS, Efremidis SC, Kirschner PA, Cohen BA. kystes bronchogéniques avec des nombres CT élevés. AJR Am J Roentgenol 1983 ;140 : 463 -465.

5:Yernault JC, Kuhn G, Dumortier P, P Rocmans, Ketelbant P, De Vuyst P."Solid" kyste bronchogénique médiastinal: analyse minéralogique. AJR Am J Roentgenol 1986 ; 146 : 73 74

6:Murayama. S, J Murakami, Watanabe H, et al . caractéristiques intensité du signal des masses kystiques du médiastin sur T1-IRM J Comput Assist Tomogr 1995 ; 19 : 188 -191.

7: Lyon RD, McAdams HP. kyste bronchogénique médiastinal: démonstration d'un niveau liquide-liquide à l'IRM. Radiologie 1993 ; 186 : 427 -428.

8:Naidich DP, Srichai MB, Krinsky GA. Computed tomography and magnetic resonance of the thorax. Lippincott Williams & Wilkins. (2007) ISBN:0781757657.