Frontal  and lateral erect radiograph of the chest reveals round opacity in mediastinum better seen at right hilum, This opacity is homogenous ,well defined margin.

CT Plain and contrast reveals well defined 3 cm diameter, round water density cystic lesion  in the region of carina,


Differential diagnosis :-

1,Bronchogenic cysts arise from an abnormality of the normal budding of the ventral foregut, the precursor of the trachea and major bronchial structures. The walls of these cysts are lined by ciliated pseudostratified columnar epithelium and may contain bronchial glands, smooth muscle bundles, and other tissues found in the tracheobronchial tree.

2.Enterogenous cysts arise from abnormal development of that portion of the dorsal foregut that becomes the gastrointestinal tract. These cysts are lined with some form of gastrointestinal epithelium. Esophageal duplication cysts are believed to arise in early development, when vacuolization of the solid early esophagus occurs to form the esophageal lumen. If an isolated vacuole fails to merge with the central esophageal lumen, a duplication cyst may occur.

3.Neurenteric cysts develop at a location in which the dorsal foregut and the primitive notochord are in close relationship. Many theories have been offered about the development of these cystic abnormalities; however, the common feature noted in many of them is that an adhesive process of some type appears to cause a vacuole of the foregut to become incorporated into the notochord tissue. The classic cyst is lined with enteric and neural tissue. They are often associated with other defects and anomalies of the vertebral column, and many cases described in the literature are those in which the cyst communicates with, or extends into, the spinal canal.

SYMPTOMS –     More than one half of patients are asymptomatic.

 Chest pain and dysphagia are the most common symptoms in symptomatic adults; in infants, symptoms are most often produced as a result of airway or esophageal compression.

 Location is more important than cyst volume in its association with symptoms of compression.

This typically shows a sharply demarcated spherical mass of variable size, most commonly located in the middle mediastinum around the carina.

When the cyst is infected or contains secretions, it may appear as a solid tumor or may demonstrate an air fluid level.

 Esophagography: A barium swallow helps to define the mass and its effect on adjacent structures.

 Complications -Infection, rupture, bleeding, and compression are common. A risk of malignant degeneration is also noted.

Other reported complications include airway-cyst fistula, ulceration, and hemorrhage.

Arrhythmias and superior vena cava syndrome may also develop.

The criterion standard is complete surgical resection.

The case of symptomatic patients is much clearer now, and lobectomy is the standard treatment. No deaths or recurrences have been reported postresection.

Long-term prognosis of asymptomatic bronchogenic cysts is unpredictable, and the potential risks are life threatening. Majority support surgical resection in these patients.