Bronchogenic Cysts - Causes, Symptoms, Diagnosis, and Treatment

Introduction

A cyst is a noncancerous abnormal sac-like structure with a definite membrane. It contains fluid, air, blood, tissue, hair, bone, or a foreign body and can occur anywhere in the body. A cyst may be congenital or acquired. It is noncancerous but contains cancerous cells sometimes. Bronchogenic cysts are congenital. They are common in infants and children but are also observed in adults.

What Are Bronchogenic Cysts?

Bronchogenic cysts are single, small, thin-walled, abnormal tissue growth. They are present from birth. They are found in the middle of the airway in the lung tissues or in the mediastinum, the area between the lungs that contains the trachea, bronchi, and bronchioles. It may be present in other regions like the neck, skin, lining of the heart, or abdomen. It remains asymptomatic but may cause infection, fever, and breathing difficulties. It compresses the adjacent structures and causes breathing, swallowing, and pain. It is removed to reduce the risk of complications.

How Do Bronchogenic Cysts Form?

Bronchogenic cysts are formed during the development of the fetus, but it is not associated with genetic mutations, and the cause is unknown. Bronchogenic cyst formation commences in the sixth week of pregnancy. Lung development starts in the fourth week of pregnancy. The bronchogenic cyst forms an abnormal outgrowth of tissue of the tracheal diverticulum. Sometimes, a part of the lung bud separates and forms a bronchogenic cyst. It is lined by respiratory (ciliated) epithelium. It consists of cartilage, smooth muscle, fibrous tissue, and mucous glands. It originates from the ventral foregut that forms the respiratory system. A bronchogenic cyst is situated close to the trachea (airway) and bronchi (trachea branches). Sometimes the bronchogenic cyst communicates with the tracheobronchial tree.

What Are the Symptoms?

Bronchogenic cysts do not present with any symptoms. Symptoms develop only if it becomes infected or grows to compress the adjacent structures.

The symptoms are:

• Fever.

• Chest pain.

• Breathing difficulties.

• Swallowing difficulties.

• Cough.

• Hoarseness of voice.

• Stridor during sleep.

What Are the Complications of Bronchogenic Cysts?

Bronchogenic cysts are not fatal but grow rapidly to cause life-threatening problems. Complications occur in 45 percent of patients but do not cause death.

The complications of bronchogenic cysts include:

• Tracheobronchial compression.

• Pulmonary infections.

• Pneumothorax.

• Pleurisy.

• Superior vena cava syndrome.

• Pulmonary artery stenosis.

• Arrhythmias.

• Air embolism in airplane passengers.

• Malignant transformation.

• Fatal myocardial infarction due to compression of the left main coronary artery.

• Dysphagia due to the compression of the gastrointestinal tract.

• Respiratory distress occurs if the cyst compresses the airway below the carinal level.

• Infection, rupture, and bleeding of the cyst may occur.

• Other complications like airway cyst fistula and ulceration can occur.

• Prenatal complications like polyhydramnios (build-up of amniotic fluid(occur due to the compression of vital organs.

How Is Bronchogenic Cyst Diagnosed?

Depending on the patient's age, bronchogenic cysts are diagnosed through various imaging tests.

• Diagnosis During Pregnancy - Bronchogenic cyst is observed during prenatal ultrasounds. The size and growth of the cyst can be determined with ultrasound and magnetic resonance imaging (MRI) scans.

• Diagnosis in Children and Adults - Bronchogenic cyst is found during a routine chest X-ray. It presents as a uniform lesion with a deviation of the trachea. It is diagnosed with the following imaging techniques:

• CT (Computed Tomography) Scan - This scan produces detailed cyst images. Sometimes, a contrast dye is used during the scan to highlight the cyst. As a result, the cyst appears as a soft tissue mass with well-defined margins.

• MRI Scan - This uses magnetic and radio waves to capture detailed images of the bronchogenic cyst.

• Esophagram - This test uses a series of X-rays to examine the esophagus (food pipe). Barium sulfate solution is swallowed before the X-ray. This helps visualize the presence of a bronchogenic cyst.

• Bronchoscopy - A bronchoscope (a small tube with an attached camera) is inserted through the nose into the airway after giving a sedative. It is used to check the presence of bronchogenic cysts and other abnormalities. In addition, under a bronchoscope, a biopsy (small tissue sample) can be done for analysis.

Bronchogenic cysts are sometimes misdiagnosed as lung abscesses, tuberculosis, or cystic teratoma.

How Are Bronchogenic Cysts Treated?

Small cysts are kept under observation, but asymptomatic cysts should also be removed to conserve the lung tissues and reduce the risk of complications. Surgical removal is the main treatment option for a bronchogenic cyst. Fine needle aspiration (a long, thin needle is used to remove the cyst) can be done, but the recurrence rate is high.

• Treatment During Pregnancy - Bronchogenic cyst is only monitored during pregnancy. Sometimes, a needle procedure may be done to drain the cyst.

• Treatment in Newborn Babies - Bronchogenic cyst is monitored if it is not causing any problems. It is removed in the labor room immediately after birth if it interferes with vital organ function. This is done when the baby is partially delivered and still receiving oxygen from the umbilical cord. This provides time for the removal of the cyst and for establishing an appropriate airway.

• Treatment in infants, children, and adults

• Thoracotomy is a surgical incision on the side, back, or between the ribs. The bronchogenic cyst is then accessed through the incision and surgically removed.

• Video Assisted Thoracoscopic Surgery (VATS) is a minimally invasive surgical procedure involving a thoracoscope (a fiber-optic camera). This does not require large incisions to access the cyst. As a result, postoperative pain and infection risk is also reduced.

• Oxygen Therapy - Patients with breathing difficulties require supplemental oxygen therapy.

What to Expect After Surgery?

The prognosis is good with the complete removal of the bronchogenic cyst. However, incomplete removal of the cyst increases the risk of recurrence.

Conclusion

A Bronchogenic cyst is a rare congenital cystic lesion located commonly in the mediastinum. Children with this cystic lesion have normal lung function due to rapid compensatory growth during childhood. Early surgical removal of the cyst minimizes complications and maximizes the compensatory growth of the lungs. Consulting the healthcare provider regarding the treatment options can help make informed decisions for long-term health.