chondromas, hamartomas, fibromas, and hemangiomas. Papillomas are associated with the human

papilloma virus and can degenerate into malignant lesions, thus requiring resection. Chondromas arise

from the cartilage, and may recur after resection. Hamartomas are comprised of cartilage, epithelial and

lymphatic tissue. Recurrence is rare after resection. Fibromas can be resected via bronchoscopy.

Hemangiomas are the most common pediatric tracheal mass. They may regress without treatment and

can be observed if not causing obstructive symptoms. Biopsy is general avoided due to bleeding risk.

Surgery may be required if lesions persist.69

Figure 80-33. Management of tracheoinnominate artery fistula. A: Common mechanism of injury from erosion of innominate

artery by adjacent tracheostomy tube. B: Emergency treatment of hemorrhage involves insertion of an endotracheal tube into the

tracheostomy stoma, inflation of the cuff, and downward and outward pressure on the fistula by the finger inserted through the

tracheostomy incision to further tamponade the bleeding. C: Through a partial upper sternal split, the segment of involved

innominate artery is resected and the oversewn ends covered with adjacent mediastinal fat or muscle. Tracheal resection is usually

not necessary. A new tracheostomy tube may have to be inserted higher in the trachea or, if possible, the tracheostomy tube

removed and the stoma covered with a sternohyoid muscle flap.

Although more common than benign lesions, malignant tracheal tumors are very rare with only 600

to 700 cases in the United States per year. Lesions may be primary tracheal lesions, tumors from

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adjacent organs growing into the trachea, or metastatic lesions.70 Primary tumors are most commonly

squamous cell carcinomas or adenoid cystic carcinomas in the trachea, followed by carcinoids in the

bronchi.70,71 Adjacent tumors may arise in the lung, esophagus, thyroid, or mediastinum. The most

common cancers that cause tracheal metastases include renal cell cancers, sarcomas, breast cancers, and

colon cancers.70 Patients will present with stridor and wheezing, and have often been recently

diagnosed with adult-onset asthma and treated with inhalers and even steroids without alleviation of

symptoms. Hemoptysis may also occur, though it is more common in lung cancer than in tracheal

disease.71 Patients should undergo imaging such as a neck and chest CT scan to assist in making the

proper diagnosis. Bronchoscopy with a flexible or rigid endoscope is essential to aid in the evaluation of

the extent of disease and to control the airway if necessary. Treatment includes tracheal resection for

primary tumors if possible. For metastatic disease, palliative treatment include endoluminal resection

and/or radiotherapy.71 Endoluminal treatments include mechanical core-out, YAG-laser treatment,

photodynamic therapy (PDT), cryotherapy, or brachytherapy. Stenting also may play a role to maintain

airway patency, either for a temporary period during radiation treatment, or in the setting of end-stage

disease (Algorithm 80-5).70

Figure 80-34. Diagrams of principal postintubation tracheal lesions. A: Cuff stenosis from the cuff of an endotracheal tube. B: Cuff

stenosis from the cuff of a tracheostomy tube, usually lower in the trachea than that from an endotracheal tube. Stomal stenosis

also occurs at the site of the tracheostomy itself. Malacia may occur either at the level of the cuff or in the segment between the

stoma and the cuff stenosis. C: Cuff stenosis at the site of a high tracheostomy stoma, which has eroded into the lower margin of

the cricoid cartilage. In older patients, this may erode back farther into the subglottic larynx, producing a laryngotracheal stenosis.

A stoma placed in the cricothyroid membrane will, by definition, produce an intralaryngeal stenosis. D: Tracheoesophageal fistula

(TEF) produced by pressure of the cuff against the “party wall,” often abetted by an indwelling firm nasogastric tube. E: One type

of tracheoinnominate fistula (TIF) as the result of a high-pressure cuff erosion. The more common type, but also rare, is that seen

with a low-placed tracheostomy stoma, which rests against the innominate artery itself. (Reproduced with permission from Grillo

HC. Surgical treatment of postintubation tracheal injuries. J Thorac Cardiovasc Surg 1979;78:860–875.)

Tracheomalacia and Airway Stents

Tracheomalacia occurs when the trachea loses its rigid form and the posterior membranous wall

approaches the anterior wall, causing luminal narrowing and obstruction leading to dyspnea. Patients

have a characteristic seal-like cough. Chest CT scans may demonstrate this condition, and pulmonary

function testing in these patients will show reduced FEV1

, FVC and peak expiratory flow rates.

Bronchoscopy is the best diagnostic test and reveals real-time airway collapse with expiration.

Etiologies include congenital tracheomalacia, extrinsic compression, postintubation stenosis and

inflammation, relapsing polychondritis, and COPD.72 Surgical intervention may include resection for

localized involvement, tracheoplasty, or stenting.72,73 Airway stents can be divided into two groups,

silicone and metal, with each type having distinct advantages (Table 80-8). Silicone stents require rigid

bronchoscopy to place, have a narrower inner lumen, and are more easily displaced. Advantages to the

use of silicone stents are that they are easily adjustable or removable, they do not develop tissue

ingrowth, and they are nonreactive to the endoluminal lining. Metal stents can be placed by flexible

bronchoscopy and conform to the trachea better. They are permanent and difficult to adjust. Placement

requires fluoroscopy, and granulation tissue often grows in between metal struts making subsequent

removal difficult.70 Newer stents being developed include covered metal stents that prevent tumor in

growth along the stent, but unfortunately still allow granulation tissue to grow in at the ends.74 In

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addition to being useful in the setting of tracheal stenosis, they can also play an essential role in

palliating posttransplant bronchial stenosis.75

Algorithm 80-5. Algorithm for management of tracheal masses. (Adapted from Wood DE. Surg Clin North Am 2002;82(3):621–642.)

Table 80-8 Classification of Airway Stents

Mediastinum

The mediastinum contains a number of important structures and may be involved in different disease

processes. Mediastinal infections are not as common as they were in the past, but when they present,

they are life-threatening situations. The mediastinum is divided into several compartments, including

the superior, anterior, middle, and posterior regions. Sometimes the lower three compartments are

extended superiorly and only three are described (Fig. 80-35). The anterior mediastinum includes the fat

and lymph nodes posterior to the sternum, but anterior to the pericardium. The middle compartment

includes the pericardium, heart, aorta, and trachea. The posterior compartment includes the esophagus,

sympathetic chain, and vertebral column (Fig. 80-36). Most lesions are found in asymptomatic patients,

but presenting symptoms include dyspnea and chest pain. Symptoms may be local, related to

compression on mediastinal structures, or systemic, caused by the release of cytokines or inflammatory

factors, such as in lymphomas or thymomas with myasthenia gravis (MG). Imaging begins with plain

radiographs, but CT scans are essential. MRI scans may be helpful to evaluate vascular or spinal

involvement. PET scans are increasingly utilized as they may further aid in staging. Biopsy and/or

surgical resection is required to confirm the diagnosis in almost all patients.76

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Figure 80-35. The mediastinal subdivisions. Note that the paravertebral sulcus encompasses the posterior compartment.

Reproduced with permission from Shields TW, ed. General Thoracic Surgery. 6th ed. 2005.

Anterior Mediastinum

The anterior mediastinum can contain a variety of tumors (Table 80-9). Most common are thymomas,

lymphomas, and germ cell tumors, in that order. Thymomas account for one-fifth of all anterior

mediastinal masses in the adult population. They arise from the thymus gland and can be seen with

autoimmune diseases such as MG and pure red cell aplasia. Tumors are usually classified by the

Masaoka classification system (Table 80-10), which looks at gross and microscopic spread of the tumor,

or the World Health Organization (WHO) histologic criteria, which is based upon the morphology of the

epithelial cells as well as the lymphocyte to epithelial cell ratio. Diagnosis is usually made by chest CT

scan. Needle biopsy of a potential thymoma is not routinely recommended for fear of seeding the needle

track. When thymomas are suspected, resection is the best option, via a midline sternotomy (Fig. 80-

37). Resection must take care to remove all of the tissue in the anterior compartment, including all fat

and tissue around the innominate vein. Entering the pleura should be avoided if possible to minimize

drop metastases into either pleural space.

Table 80-9 Location of Primary Mediastinal Masses in Adults and Children

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Figure 80-36. Normal mediastinal anatomy as shown with computed tomography scans. A: Scan at level of the aortic arch and

midtrachea. T, trachea; E, esophagus; AA, aortic arch; SVC, superior vena cava. B: Scan at level of carina. RULB, right upper-lobe

bronchus; LMB, left mainstem bronchus; AA, ascending aorta; DA, descending aorta; A, azygos vein; PA, main pulmonary artery;

LPA and RPA, left and right pulmonary arteries. C: Scan at the level of the left atrium. LA, left atrium; RA, right atrium; LVOT, left

ventricular outflow tract; RV, right ventricle.

Table 80-10 Masaoka Staging System for Thymoma

Thoracoscopic approaches to resect thymomas have been described, but some surgeons question this

approach due to the potential increased risk of drop metastases, and thus the potential for a poorer

oncologic outcome. Neoadjuvant chemotherapy and radiation may be used to downstage Masaoka III

and IV stage tumors and allow for subsequent resection. Postoperative radiation is recommended for

Masaoka stage III tumors, and may be considered for stage II disease. Platinum-based chemotherapy is

typically utilized in the unresectable setting.77 MG presents with diplopia, ptosis, fatigue, and weakness.

One-third to one-half of patients with thymomas have MG, but only 10% of patients with MG have

thymomas. Antiacetylcholine receptor antibody levels may be measured to evaluate for MG in patients

with suspected thymomas.78 Thymic carcinomas and thymic carcinoids are other tumor types that can

also arise from the thymus.

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Germ cell tumors can present as benign teratomas, seminomas, and embryonal tumors, which include

nonseminomatous germ cell tumors and malignant teratomas. Benign teratomas have a good prognosis

and resection is the best treatment. Seminomas comprise upto half of mediastinal germ cell malignant

tumors. Patients may have symptoms from local compression or systemic symptoms such as fever,

weight loss, and even gynecomastia. These tumors are radiosensitive, but in locally advanced disease,

chemotherapy with later surgical resection is the favored treatment. Nonseminomatous tumors include a

wide variety of histologic malignancies. They usually occur in young men and are often symptomatic

(Fig. 80-38). Elevated alpha-fetal protein (AFP) and beta-human chorionic gonadotropin (β-hCG) levels

are seen with these tumors and should be measured. Chemotherapy is the best treatment, but patients

have a poorer prognosis when compared to those with seminomas. Lymphomas in the mediastinum are

usually part of a wider spectrum of disease. Two-thirds of cases are Hodgkin disease. Most patients

present with symptoms of fevers, night sweats, and even weight loss. Treatment is always

chemotherapy-based, and surgery in the form of a biopsy is utilized only to help make the diagnosis.78

Figure 80-37. Thymic resection. A: Exposure of thymus via median sternotomy. B: Elevation of thymus completely off of the

pericardium. C: Pulling the thymus inferiorly to resect the right superior horn (and later the left superior horn). (Reproduced with

permission from Scott-Conner CE, Dawson DL, Shirazi MK, et al. Operative Anatomy. 3rd ed. Philadelphia, PA: Lippincott Williams

& Wilkins; 2008.)

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Figure 80-38. Computed tomography scan of a malignant nonseminomatous germ cell tumor of the anterior mediastinum reveals

the inhomogeneous anterior mediastinal mass in contrast to the homogeneous density of a seminoma. Pleural effusion is also

demonstrated in the right hemithorax. (Reproduced with permission from Shields TW. Primary lesions of the mediastinum and

their investigation and treatment. In: Shields TW, ed. General Thoracic Surgery. Baltimore, MD: Williams & Wilkins; 1994:1724–

1769.)

Figure 80-39. Computed tomography scan reveals a bronchogenic cyst located in the subcranial area with compression of the left

mainstem bronchus with hyperinflation of the left lung and a mediastinal shift to the right. (Reproduced with permission from

Shields TW. Primary lesions of the mediastinum and their investigation and treatment. In: Shields TW, ed. General Thoracic Surgery.

Baltimore, MD: Williams & Wilkins; 1994:1764–1769.)

Middle and Posterior Mediastinum

Middle mediastinal masses include esophageal and bronchogenic cysts, pericardial cysts,

lymphangiomas, and lymphomas (Fig. 80-39). For cystic lesions, surgical resection is the best treatment

option. Posterior lesions include neurogenic tumors which may be benign or malignant. Almost 95% of

tumors come from the sympathetic chain or intercostal nerve rami. Upto two-thirds of these tumors are

benign nerve sheath tumors and are usually discovered incidentally. A MRI scan may be used to

evaluate intraspinal extension.78

Pediatric Mediastinum

The presentation of mediastinal masses in the pediatric population varies from what is observed in

adults. The rate of malignancy is slightly lower in children, and while thymomas are the most common

adult masses seen, neurogenic tumors are more common in children (Table 80-11). Just over half of all

mediastinal tumors arise in the posterior compartment.79 Anterior masses may include the normal

thymus in a young child. Teratomas are the most common germ cell tumor seen.79 Vascular anomalies

may be seen in children and include hemangiomas and cystic hygromas.80 Middle compartment tumors

are usually foregut cysts, as in the adult population. Posterior tumors are most often malignant

neurogenic tumors, compared to more benign pathology in adults.79

Mediastinitis

9 Mediastinal inflammation can arise from different sources, but it is most often infectious in nature.

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