Bronchogenic Cyst

Bronchogenic Cyst Definition

These are cysts or sinuses that are small in size and are solitary. They are located in the region of suprasternal notch or over the manubrium. This type of cyst arises due to a congenital malformation of the bronchial tree.

Bronchogenic Cyst Types

Two types of such cysts are found to occur. These are:

Picture of Bronchogenic Cyst

Picture 1 – Bronchogenic Cyst

Mediastinal

This cyst is located in adjacent to the tracheobronchial tree. In this case, abnormal separation of bud takes place in the initial years of development. Hence, the cyst is located near the tracheobronchial tree. It is non- infectious in nature and has got no connection with the bronchial tree. Air fluid levels are not usually seen.

Intrapulmonary

These cysts are found to be located inside the lung parenchyma. They get infected often and also communicate with the bronchial tree. The abnormal bud separation takes place later when the lung develops. Thus, the cysts are found inside the lung enveloped by lung parenchyma. Air fluid level is noticed when there is interaction with the bronchial tree.

Bronchogenic Cyst Causes

These cysts occur due to abnormal budding of the bronchial tree during embryogenesis. They are lined with secretory respiratory epithelium. Generally, the cysts do not communicate with the bronchial tree and are therefore not filled with air. However, they contain water, varied amounts of proteinaceous material, blood products and calcium oxalate. These three elements cause excess enlargement leading to formation of solid lesions. A cyst of this form can occur as a mediastinal mass whose increased size causes local compression.

Bronchogenic Cyst Symptoms

They are made of cartilage, smooth muscle, fibrous tissue and mucous glands. These cysts begin from the ventral foregut which forms the respiratory system. These are considered to be one of the most common foregut duplication cysts.

The symptoms are more prominent and frequent in children and are quite rare in adults. The small thoraic volume and the malleable airways make children prone to compressive symptoms early in life. The general symptoms of this disorder are:

  • Dysponea
  • Coughing
  • Chest pain
  • Dysphagia

These types of cysts are asymptomatic in case of adults.

Some other signs are:

  • Superior vena caval syndrome
  • Hemothorax
  • Hemoptysis
  • Empyema
  • Cyst ruptures

Cerebral air embolism and compression of heart leading to arrhythmia are also noticed.

Bronchogenic Cyst Diagnosis

The diagnostic procedures for this abnormal condition include:

Chest X-ray

Through this test, the cyst of intrapulmonary type looks like a cyst of variable size inside the lung parenchyma. The mediastinal Bronchogenic cyst looks smooth rounded and opaque in the mediastinal which is adjacent to the tracheobronchial tree.

MRI of the Chest

The MRI technique is used to detect increased protein content in the cyst fluid when the infection spreads. The cystic mass is noticed in the mediastinum.

Bronchoscopy

This method reveals features formed due to compression of airways. This begins from the cyst, blood clots and interactions with the cyst cavity are also found.

Ultrasound

Ultrasound is opted to check the cystic nature of the mediastinal lesion. This method is successful in case of infants and children. Sometimes, antenatal ultrasound tests can detect a Bronchogenic cyst.

Cyst aspiration

The cyst is to be aspirated under radiological guidance via EBUS, also known as thoracic approach, and sent for cytology. The existence of mucous and bronchial epithelial cells confirms Bronchogenic type of cyst.

Endoscopic Ultrasound

If the cyst is situated close to the gastrointestinal tract, this method is used to evaluate it.

Trans esophageal Echo

This process helps in differentiating between pericardial cysts from the Bronchogenic cyst.  

Barium tests

These tests are required to check if there is any fistulous activity connected with the gastro intestinal tract and to evaluate if the cyst is suppressing the GI channel.

Endobronchial Ultrasound

It can be used to evaluate the cystic nature of the lesion. In this exam, the fluid is tested for cytological analysis to confirm the diagnosis.

CT-Chest

In this test, the cysts look like round-shaped, unilocular and sharp circumscribed structures having thin walls. Accumulation of fluids and air inside the cysts can be noticed in this test. The consistency of the cystic fluid varies due to the presence of excess mucous and protein due to infection. This fluid will give the cyst an appearance of a soft tissue mass sometimes. Traces of calcium deposits also get revealed in this test.

Differential Diagnosis of Bronchogenic Cyst

The cystic lesion of the thorax cannot be detected through significant percentages. Thus, there are few differential diagnosis tests for individuals diagnosed with these cysts.

Mediastinal Bronchogenic cysts might be similar to:

  • Lymphoma
  • Hydatid cysts
  • Pericardial cysts
  • Enteric cysts

Intrapulmonary cysts are quite similar to:

  • Lung abscess
  • Fungal disease
  • Vascular malformations
  • Hydatidosis
  • Tuberculosis
  • Neoplasms

Physicians should use specific tests to determine whether an individual in actually infected with Bronchogenic cysts or any of the above vesicles.

Bronchogenic Cyst Treatment

All cysts of this nature must be treated by surgical excision. This is important as all cysts are prone to get infected and become malignant. These lesions need to be excised with caution as they carry the risk of bleeding or infection of the cyst later which makes the process more difficult. Thoracoscopic resection is another method to treat these vesicles. This method involves a lot of significant advantages such as proper cosmesis, reduced risk of rib fusion and less pain. Patients who exhibit symptoms and cannot opt for surgical procedures should be treated via procedures like transparietal, transbronchial, mediastinal puncture and aspiration. In newborns, these cysts do not show any symptoms. Therefore, they should be operated at the age of 3-6 months to allow the lungs to recover and facilitate growth.

Bronchogenic Cyst Complications

These cysts frequently give rise to complications. Generally, the complications occur due to compression of structures in the surroundings. Infection is another common problem in the cysts that have connections with the bronchial tree. The cyst can also rupture into the trachea, the pericardial activity, and into the pleural cavity as well. Pneumothorax is the other complexity which usually takes place along with pleuritis. Severe case of hemoptysis has also been reported.

Other complications of this condition may include:

Image of Bronchogenic Cyst

Picture 2 – Bronchogenic Cyst Image

  • Adenocarcinoma
  • Pleuropulmonary blastoma
  • Leiomyosarcoma
  • Rhabdomyosarcoma
  • Anaplastic carcinoma

 

These cysts are life-threatening when they compress the airway and other vital structures.  They can prove to be fatal in cases of small children and infants as they tend to suppress vital structures in the body resulting in respiratory problems. Naturally, an immediate diagnosis and treatment of these vesicles is extremely important.

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