Transcript MEDIASTINAL BRONCHOGENIC CYSTS OF ADULTS: Report …

CH2
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
INTRODUCTION

Bronchogenic cysts are one of the most common
bronchopulmonary malformations.

Modern imaging techniques such as CT and MRI are
useful for precise preoperative diagnosis.

However, despite advances in diagnostic imaging, the
definitive diagnosis of a mediastinal bronchogenic
cyst is histological.
The aim of our study is to:

Recall the etiopathogenesis, epidemiological
and clinical data of mediastinal bronchogenic
cysts

Illustrate the imaging appearance in different
modalities of exploration
MATERIALS AND METHODS

Retrospective study of 5 cases of mediastinal bronchogenic
cysts in adults explored in our service over a period of 9 years.

Chest radiography and chest CT were performed in all cases;
MRI was realised in only one case.

Surgical resection was performed in all patients.

Histopathological study confirmed the diagnosis
RESULTS

We found in our series 4 women and 1 man with an average age of
50 years.

No pathologic history
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The cyst was discovered incidentally in 3 cases on the chest
radiography; by dyspnea in one case and a chronic cough in other
case.

The cyst was located in the middle mediastinum in 4 cases and in
the anterior mediastinum in 1case.

The mean diameter of the cyst was 6.7 cm.
RESULTS

Pathological examination of the surgical
specimen led to the diagnosis in all cases.

The postoperative course was unremarkable.

The subsequent evolution was favorable
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 anterior
right 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 with
pleural 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
Embryological recall

Bronchogenic cysts result from abnormal budding of the ventral
foregut that occurs between the 26th and 40th days of gestation.

They
are
lined
with
pseudostratified
columnar
respiratory
epithelium, and their walls usually contain cartilage, smooth muscle,
and mucous gland tissue(1).

They may be filled with clear, serous fluid or thick, mucoid
material.
Epidemiology

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 other
congenital pulmonary malformations such as sequestration and lobar
emphysema(2).

They may undergo an abrupt increase in size as a result of hemorrhage
or infection
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).
Imaging findings
1. Chest radiographs:

It
is
usually
adequate
for
detecting
larger
mediastinal masses as a homogeneous opacity ;

But, it is limited in the tissue characterization of the
lesion

Imaging findings
2. CT scan:

It is used to characterize the mass and clarify its
relationship to adjacent mediastinal structures.

It is characteristic when the lesion demonstrates a
homogeneous fluid attenuation mass with a thin or
imperceptible wall.
Imaging findings
2. CT scan:
!

The attenuation value is dependent on the contents of the cyst.

It can vary from water attenuation to soft-tissue attenuation.

The value can be more than 100 HU owing to a high protein level or
calcium oxalate in the mucoid cyst(4,5).

Air within the cyst is uncommon and suggestive of secondary
infection and communication with the tracheobronchial tree.

Calcification occurs occasionally in the wall or within the cyst
contents.
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-weighted images, variable patterns of signal intensity are
seen because of variable cyst contents and the presence of
protein, hemorrhage, or mucoid material(6).

A fluid-fluid level within the bronchogenic cyst may be seen(7).
Differential diagnosis

It arises with other cystic lesions of the mediastinum including :

Congenital benign cysts : duplication cysts, neurenteric cysts,
meningocele, pericardial cysts, thymic cysts, cystic teratoma,
and lymphangioma.


Mediastinal abscess

Pancreatic pseudocyst
Clinical history, anatomic position, associated abnormalities
and imaging semiology
cases.
allow correct diagnosis in many
Treatment

The choice of treatment is controversial.

Some authors advocate surgical excision of all cysts given
their tendency to become infected or rarely, to undergo
malignant transformation(8).

Increasingly, these lesions are treated with transbronchial or
percutaneous aspiration under CT guidance to both confirm
the diagnosis and to treat them.

Small lesions can be followed.
Intraoperative appearance of bronchogenic
cyst
Intraoperative aspiration of bronchogenic cyst.
CONCLUSION

A cystic mediastinal mass with a thin or
imperceptible wall in a subcarinal location should
be a bronchogenic cyst.

In cases where the cystic nature is not apparent on
CT, the high signal intensity on T2-weighted
images should confirm the cystic nature.
REFERENCES
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