Cyst (from Greek: kystis = bladder) is a tissue cavity closed by a membrane (epithelium) , which can be chambered and contains fluid.

Bronchogen: Arising from the tissue of a bronchus.

Foregut : The oral section of the primitive gut tube that is created during embryonic development (in the womb).

Mediastinum (mediastinal cavity): Vertical tissue space in the chest cavity. It extends from the diaphragm to the neck and is bounded anteriorly by the sternum and posteriorly by the spinal column.

The entire gastrointestinal tract is created in various stages during the development of the embryo. First, a "primitive" intestinal tube is formed, the first (oral) section of which is called the "foregut". The pharynx, larynx, oesophagus, stomach and the first part of the duodenum develop from this foregut. The trachea and lungs also develop by sprouting from the foregut.

If this sprouting (budding) takes an abnormal course, a cyst can form in the anterior (ventral) part of the foregut. This is called a bronchogenic cyst.

Although bronchogenic cysts are rare, they account for approx. 40-50% of all masses in the mediastinum (see above). However, they can also occur in the lungs (intrapulmonary). Other localizations are in the neck area or rarely even below the diaphragm. There is no connection to the trachea or bronchi, so the cysts do not contain air.

2/3 of all patients present in infancy with symptoms resulting from the location and size of the cyst: Cough, loud inhalation noise (so-called "stridor"), shortness of breath or inflammation of the airways (pneumonia) or recurrent bronchitis. Occasionally, the diagnosis is made before birth if a cystic structure in the mediastinum is seen on ultrasound during the LINK prenatal consultation. As there are various congenital malformations in this area (LINK CPAM; LINK Congenital lobar emphysema; LINK Lung sequestration), it is correct to speak of a "congenital thoracic malformation" at this time.

After birth, a bronchogenic cyst can be detected as a dense, roundish structure in a chest X-ray. In the subsequent computer tomogram or magnetic resonance tomogram of the chest (CT or MRI), the bronchogenic cyst appears as a mucus-filled structure without the inclusion of contrast medium.

In older children, bronchogenic cysts are usually discovered completely by chance on chest X-rays taken for other reasons.

Bronchogenic cysts should be removed completely, even in children who have no symptoms, due to the risk of complications such as infection and malignant degeneration of the cyst wall. If the cyst is located within the lung (intrapulmonary), the aim is to remove it locally while sparing the surrounding lung tissue. Removal of the affected lobe of the lung (lobectomy) is only rarely necessary.

Initial contact is made either during an outpatient information session at our pediatric surgery outpatient clinic (see below for contact details) or on the ward where your child is being cared for. The treatment options will be presented and your questions will be discussed in detail. Please bring all available examination results with you to the first information meeting. The final indication for surgery is always made together with the Clinical Department of Paediatric Pneumology, Allergology and Neonatology in the interdisciplinary thoracic conference.

The following are common examinations that are carried out in the case of a bronchogenic cyst:

1. X-ray examination of the chest
   
2. Computed tomography or magnetic resonance imaging of the chest:
   These procedures, also known as "cross-sectional imaging", can be used to precisely determine the localization and size of the bronchogenic cyst. The information is primarily used by the pediatric surgeon to assess which surgical procedure (open or thoracoscopic) is most suitable for your child.
   
3. (X-ray) pulp swallowing examination
   This examination may be useful in individual cases. It does not detect the cyst itself, but rather its outline by visualizing the esophagus. To do this, your child must swallow a special gruel that is not permeable to X-rays. The transport of the gruel through the oesophagus and its course can then be examined, particularly with regard to the localization of the cyst.

If your child has been diagnosed with a bronchogenic cyst and the indication for surgery has been discussed in detail with you, your child will be admitted to our pediatric surgery wards. The operation can be performed either minimally invasive or open.

Minimally invasive surgical technique / thoracoscopic resection

Depending on the location of the bronchogenic cyst, three or four small incisions (approx. 3-5 mm) are made on the right or left side of the chest using the thoracoscopic (minimally invasive) surgical technique. A thin tube (trocar) is inserted into the chest cavity through each of these incisions. Air is also blown into the chest cavity through one of these trocars and a camera is inserted (thoracoscopy). This allows the affected unilateral chest to be inspected. The remaining trocars are used to insert the small instruments required to remove the cyst.

In most cases, a small drainage tube (so-called thoracic drainage or pleural drainage) is placed in the pleural cavity (the space between the surface of the lung and the pleura) in order to maintain or restore the physiological negative pressure. Sometimes a controlled suction is also applied, which serves to pump wound secretions or air out of the pleural cavity. However, this drainage is usually removed again soon after the operation.

Not all children can undergo minimally invasive surgery. Factors such as birth weight, the extent of the cyst, other malformations (such as heart defects) and, above all, the urgency of the treatment play a role here. The pediatric surgeon may also have to switch to an open surgical technique for technical reasons, for example if the overview during thoracoscopy is inadequate.

Surgical technique

The main difference between the open surgical technique and the minimally invasive technique is the way in which the surgical site is accessed. Instead of three or four small incisions, a single, longer incision is made over the respective intercostal space - depending on the location of the cyst - to provide access to the surgical area. With this technique, it may also be necessary to insert a chest drain, which is quickly removed again.

We always use absorbable suture material. Therefore, no suture removal is necessary after the operation. If a chest drain was inserted during the operation, it will be removed a few days after the operation. Scarring depends on the individual's disposition.

Patients with a bronchogenic cyst have to stay in hospital for a few days after the operation. During this period, the child and mother are cared for by our pediatric nurses and the medical team on LINK pediatric surgery ward 66.

3 months after removal of the bronchogenic cyst, the child will be seen again in our pediatric surgery outpatient clinic. Here we carry out both a clinical and a radiological (chest X-ray) follow-up. Thereafter, annual follow-up examinations may follow until adolescence, in the event of symptoms also at short notice and, if necessary, together with our LINK Clinical Department of Paediatric Pneumology, Allergology and Neonatology.