Bronchial Adenomas/Carcinoids, Childhood

The term bronchial adenoma describes a diverse group of tumors arising from mucous glands and ducts of the trachea (windpipe) or bronchi (large airways of the lung). This term describes all of the following types of tumors: neuroendocrine tumors (carcinoids), adenoid cystic carcinomas (cylindromas), mucoepidermoid carcinomas, mucous gland adenomas, and other mixed seromucinous tumors arising from mucous glands and ducts of the windpipe and large airways.

These tumors are of widely variable malignant (cancerous) potential, although most of them are low-grade malignancies, growing and spreading much more slowly than true lung cancer. Only mucous gland adenomas are truly benign (noncancerous), lacking even the potential to turn malignant.

Bronchial adenoma may remain undiagnosed for years because of the small size of the tumor and the slow growth pattern. This condition masquerades as bronchial asthma, chronic bronchitis, or bronchiectasis (localized irreversible expansion of part of the bronchial tree resulting in airflow obstruction and impaired clearance of secretions).

Symptoms of bronchial adenoma depend on whether the tumor is located centrally or peripherally in the airways. Persons with central lesions have symptoms of obstruction and bleeding, which include the following:

• Dyspnea (difficulty breathing) is caused by partial obstruction of the windpipe or large bronchi.
• Stridor (abnormal sound produced by turbulent flow of air through a narrowed part of the larger airways) can be present when the adenoma is in the windpipe or large bronchi.
• Wheezing (high-pitched whistling sound produced by the flow of air through narrowed smaller airways) is heard if the obstructed air passages are further out in the large bronchi.
• Cough, fever, and sputum production result from complete obstruction of the bronchi, leading to collapse, infection, and destruction of the lung tissue on the other side of the obstruction.
• Coughing up blood results from ulceration of the lining of the airway overlying the tumor and is fairly common in bronchial adenoma. Coughing up blood is a danger sign and nearly always indicative of a serious disease, whether bronchial adenoma or another lung condition.

Persons with peripheral lesions are more commonly asymptomatic (that is, they do not have any symptoms). The peripheral lesions most often appear as solitary pulmonary nodules on chest x-ray films. Because these individuals are asymptomatic, the findings are typically found on chest x-ray films taken for other reasons

Diagnosis and Treatment:

Although bronchial adenoma may remain undiagnosed for years because of the small tumor size and the slow growth pattern, people should be aware of its symptoms, particularly breathing difficulties and obstruction. Because coughing up blood is a danger sign and nearly always indicative of a serious disease, immediate medical attention is warranted in these cases.

• Chest x-ray films may demonstrate a nodule (less than 3 cm in diameter) or a larger mass of tumor. Oblique-view chest x-ray films may improve the ability to detect central lesions on chest x-ray films.
• Computed tomography (CT) scan of the chest allows a better assessment of the tumor. The doctor can tell how big the tumor is, exactly where it is located in the lung, and whether it looks like it is spreading to the lymph nodes.
• Magnetic resonance imaging (MRI) is generally used when CT scan findings are unclear.

None of the above techniques accurately differentiate bronchial adenoma from other neoplasms (growths).

• Octreotide nuclear scan is a test used to detect carcinoid tumors and to determine sites to which they have spread.
• Bronchoscopy: This procedure is used to visualize the inside of the trachea (windpipe) and large airways in the lung for abnormal growths. After giving the person a sedative, the doctor numbs the throat and windpipe with local anesthesia. A bronchoscope (a thin, flexible, lighted tube with a tiny camera at the end) is inserted through the mouth or nose and then down the windpipe. From there, the bronchoscope can be used to look at the airways (bronchi) of the lungs. During bronchoscopy, the doctor may perform a biopsy (a sample of cells removed for examination under a microscope) on the tumor.
• Transbronchoscopic fine-needle aspiration: If the lesion is not easily accessible on the airway wall or is less than 2 cm in diameter, a fine-needle aspiration biopsy may be performed as a part of the bronchoscopic examination.
• CT-guided fine-needle aspiration: If a peripheral nodule is present, a needle may be inserted through the chest wall, between the ribs, and placed in the nodule. This biopsy specimen can be examined under the microscope to determine if the nodule is benign (noncancerous) or malignant.

If these tests are nondiagnostic and if malignancy is likely, a thoracoscopic procedure or an open thoracotomy (incision through the chest wall) may be performed. If a person has been diagnosed with bronchial adenoma, the tumor is removed through bronchoscopic surgery; open lung surgery; or video-assisted thoracic surgery (VATS), a form of minimally invasive surgery.

Bronchoscopic surgery may be performed if the tumor is small and limited to the airways. In this surgery, the tumor may not be completely removed. Also, the chances of profuse bleeding are higher. Therefore, bronchoscopic surgery for tumor removal is only recommended in people who cannot undergo open lung surgery or VATS because of other health conditions.

The tumor can also be ablated through the bronchoscope using a laser. However, this method is not recommended as a primary mode of tumor removal and is usually used only for recurrent tumors.

Follow up care:

Chemotherapy and radiotherapy can be instituted if indicated, as discussed in Medical Care.

Transfer

If the endoscopist is not prepared to deal with airway bleeding, biopsy should be deferred until the patient has been sent to an appropriate facility.

Deterrence/Prevention

No preventive regimen has been established. Smoking cessation is always a good thing but has no specific effect on these tumors.

• Delayed hemorrhage
• Bronchial anastomotic leak
• Coagulopathy
• Myocardial ischemia
• Need for persistent mechanical ventilation
• Mucoepidermoid carcinoma - Known to result in intracranial metastases, even in cases of minimal bronchial wall involvement
• Carcinoid - Solid organ metastases (eg, to the liver) possible

Prognosis

The overall 5-year patient survival rates for bronchial adenomas are excellent at approximately 96%. Scattered reports describe local recurrences or distant metastases following adequate resection of typical lesions.

Carcinoids

The slow growth pattern of carcinoids often prolongs the natural history of the disease process. A 5-year patient survival rate of 92% and 10-year survival rate of 88% has been reported for typical carcinoids treated with complete resection and formal mediastinal dissection. These excellent results applied to patients with both N1 and N2 disease, although those with N2 status received adjunctive radiation therapy. In atypical carcinoids, the survival rate is decreased to 60% at 5 years and 49% at 10 years.

Adenoid cystic carcinoma

After resection, the 5-year survival rate is approximately 83% and the disease-free survival rate is 60%. Patients with adenoid cystic carcinoma have an excellent prognosis because the tumor grows slowly and is radiosensitive. The best results are achieved when complete resection is accomplished; however, prolonged patient survival is possible even with incomplete resection.

Mucoepidermoid carcinoma

The 5-year survival rate is 11.1%. This tumor is known to cause intracranial metastases, even in the presence of minimal bronchial wall involvement. Chemotherapy and radiation are used mainly for palliation.

Patient Education

For excellent patient education resources, visit eMedicine's Procedures Center. In addition, see eMedicine's patient education article Bronchoscopy.

Medicolegal Pitfalls Failure to diagnose

The most common medicolegal hazard is failure to diagnose. Patients with bronchial adenoma may present with hemoptysis, chronic cough, recurring pneumonia, or simple chest discomfort. While radiographs may show segmental or lobar atelectasis or infiltrate, the tumor itself is rarely large enough to be visible and radiographic findings may be completely normal.

CT scanning should always be performed if the radiograph continues to show atelectasis over a period of 2-3 months. Definitive diagnosis is made with bronchoscopy. Hemoptysis almost always prompts bronchoscopy, but the general clinician should remember that chronic cough and recurring pneumonia are also indications. No physician should be sued successfully if an honest effort is made to diagnose persisting atelectasis or recurring pneumonia, but that effort should generally include CT scanning and bronchoscopy.

Bleeding

Bronchoscopic biopsy may lead to bleeding, which can be severe and life threatening. Occasional reports describe spontaneous severe bleeding, or the tumor can bleed following biopsy. Any bleeding in the airway can be life threatening; however, this bleeding can usually be controlled using conservative measures. The availability of argon-beam electrocoagulation in the bronchoscopic suite can be beneficial.

Bleeding following bronchoscopy is the most dangerous pitfall. If the endoscopist is not prepared to deal with airway bleeding, a biopsy should be deferred until the patient has been sent to an appropriate facility.

Some surgeons believe the bronchoscopy should always be performed through a straight bronchoscope, but, with current equipment, fiberoptic bronchoscopy is safe. A straight bronchoscope permits better control of a bleeding biopsy site than a flexible bronchoscope, but the fiberoptic bronchoscope allows more complete inspection of all orifices and all segmental branches.

To successfully deal with bleeding, endotracheal intubation should be available and the operator should have the ability to intubate and to use an endotracheal tube to tamponade the bleeding tumor, or at least to block off the bronchus on the bleeding side to permit ventilation through the nonbleeding side. Rigid bronchoscopy should be available within the facility.

Failure to perform a biopsy

Because of the risk of bleeding, many clinicians have fallen into an associated pitfall, which is a failure to perform a biopsy on anything in the tracheobronchial tree that looks as if it may be a bronchial adenoma. To avoid this, perform the biopsy but be prepared to handle any hemorrhage.

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