Bronchogenic cysts are rare congenital malformations of the anterior intestine5. This malformation can occur during the 3rd and 4th gestational week, when the primitive gut tube divides dorsally into the eventual esophagus, and ventrally into the eventual pulmonary yolk and tracheobronchial tree2. During development of an intrapericardial bronchogenic cyst, the heart and lungs share a common celomic cavity, thus the pulmonary yolk separation and its inclusion in the pericardial cavity can occur simultaneously5. Based on the location, they can be classified as parenchymal or mediastinal, the latter being more common in 86% of cases2. Additionally, they may also be classified as precarinal (52%), paratracheal (19%), paraesophageal (14%), and retrocardiac (9%)2. Occasionally, they may be present in other locations such as subcutaneous, cutaneous, neck and diaphragm, however the intrapericardial and intracardiac are extremely rare in the literature5. Their size often varies on average from 2–4 cm2 [Table 1].
Table 1
Comparison of Reports of Bronchogenic Cysts in the Literature.
Authors
|
Age (years)
|
Gender
|
Size (cm)
L x W x H
|
Location
|
Treatment
|
Extracorporeal Circulation
|
Maldonado J et al.
|
66
|
Female
|
8 × 6 × 0.3
|
Pericardial
|
Resection
|
Yes
|
Qu X et al.5
|
1.6
|
Female
|
5.3 × 3.6 × 2.8
|
Pericardial
|
Resection
|
Not described
|
Li Z et al.9
|
17
|
Male
|
9 × 8.4
|
Left atrium
|
Resection
|
Yes
|
Olsen M et al.10
|
50
|
Female
|
3.4 × 3.3 × 4.1
|
Interatrial septum
|
Resection
|
Yes
|
Wang J et al.11
|
41
|
Female
|
2.5 × 1.5 × 2
|
Left ventricle
|
Resection
|
Yes
|
Borges AC et al.12
|
43
|
Female
|
4.4 × 3.4
|
Interatrial septum
|
Resection
|
Not described
|
Forcillo J et al.13
|
41
|
Female
|
1 × 1.7 × 1.2
|
Left ventricle
|
Resection
|
Yes
|
Nishida N et al.14
|
73
|
Male
|
0.5
|
Interventricular septum
|
Death
|
N/A
|
Often asymptomatic, in 19% of cases, the cysts are usually diagnosed as incidental findings on chest x-rays2,3. Typical symptoms may include retrosternal chest pain, dyspnea, coughing, stridor, fatigue, weakness, anorexia and fever2,5,3. Clinical manifestations depend on the localization of the mass, its size and whether it exerts any compression on adjacent structures5. If the cyst is small enough, avoiding any adjacent structures, it is usually asymptomatic. When the cyst is large, it usually produces coughing, chest pain, respiratory difficulty or even dysphagia. In adults, most cysts are very small reducing the chance of any ongoing symptoms1, however in this case report we show a large cyst generating important clinical manifestations, including heart failure and a cardiac arrhythmia.
A CT scan is used to identify location, size, shape, and its relation with adjacent structures, however it only accurately identifies these characteristics in 10–40% of patients7. Other patients often require additional studies such as an MRI, which has shown a higher diagnostic use given its high signal intensity in T2 images8. Additionally, the MRI can be useful for determining the origin of the cyst lesion, its relation with other structures and can even determine the best surgical approach7. In this case report, the chest CT scan was not enough to provide an adequate characterization of its walls and relation to adjacent structures, hence warranting a cardiac MRI.
The definitive diagnosis of a bronchogenic cyst is histopathological, once surgical resection is completed3. The typical findings are cysts with ciliated columnar epithelial cells along the inner lining8. The internal wall can also contain cartilage and smooth-muscle tissue, however these are not essential for the diagnosis. In this case, the cyst had ciliated columnar epithelial cells with fibromuscular tissue and mature cartilage of the inner wall, confirming the bronchogenic cyst diagnosis.
The definite treatment is surgical resection; this includes asymptomatic patients so as to avoid later complications such as infection, rupture or malignity2,5. Prognosis without treatment has a 100% mortality rate, which is reduced to 0–14% in surgical management2. In this case report, given the intrapericardial location, an extracorporeal circulation with bicaval aortic cannulation was required to ensure an adequate visualization and subsequent resection. In previous intracardiac and intrapericardial case report series, results have shown most of these cysts require extracorporeal circulation to undergo successful resection.