Chapter 5

Chest Wall, Lung, and Mediastinum

D. Bruce Panasuk

William R. Alex

Richard N. Edie

I Disorders of the Chest Wall

A Chest wall deformities

Pectus excavatum (funnel chest). An exceedingly depressed sternum is the most common chest wall deformity. It is usually asymptomatic, but it may cause some functional impairment. Surgery is indicated for moderate to severe deformities and is performed at 4–5 years of age. The operation involves

Subperichondrial resection of all involved costal cartilages

An osteotomy of the sternum

Overcorrection of the sternal defect with a bone wedge

Use of a retrosternal support (optional)

Pectus carinatum (pigeon breast). An overly prominent sternum is less likely to cause functional impairment than a depressed sternum. The repair is similar to that used for pectus excavatum.

A distal sternal defect occurs as part of the pentalogy of Cantrell (see Chapter 29, III A 2 d).

Poland's syndrome is a unilateral absence of costal cartilages, pectoralis muscle, and breast. Surgery is indicated for protection of the underlying thoracic structures and for cosmetic reasons.

Thoracic outlet syndrome (TOS)

Clinical presentation

Compression of the neurovascular bundle at the thoracic outlet (by fibromuscular bands, the anterior scalene muscle, the first rib, or the cervical ribs) causes pain and paresthesia in the neck, shoulder, arm, and hand.

Brachial plexus compression (neurogenic TOS) occurs most often. Pain affects the neck, shoulder, anterior chest wall, and arm. Paresthesia predominantly affects the hand, often in an ulnar nerve destination.

Vascular compression (vasculogenic TOS) occurs much less frequently.

Diagnosis is clinical and is based on a careful history and detailed physical examination. Electrodiagnostic studies provide little help in establishing brachial plexus compression, although these studies more reliably rule out peripheral neuropathies. Cervical disk disease must be ruled out by magnetic resonance imaging (MRI).

Treatment is initially conservative, using a focused physical therapy program for 3–6 months. Patients with refractory symptoms can be offered surgery, which involves brachial plexus decompression by way of supraclavicular scalenectomy, brachial plexus neurolysis , or first rib resection.

B Chest wall tumors

Benign tumors

Fibrous dysplasia of the rib occurs posteriorly or on the lateral portion of the rib. It is not painful, and it grows slowly. It may occur as part of Albright's syndrome.

P.107

Chondroma is the most common benign tumor of the chest wall. It occurs at the costochondral junction.

Osteochondroma occurs on any portion of the rib.

Malignant tumors include fibrosarcoma, chondrosarcoma, osteogenic sarcoma, myeloma, and Ewing's sarcoma.

Treatment of chest wall tumors involves wide excision and reconstruction, using autologous grafts, prosthetic grafts, or both.

II Disorders of the Pleura and Pleural Space

A

Spontaneous pneumothorax occurs when a subpleural bleb ruptures into the pleural space with resultant loss of negative intrapleural pressure, allowing the lung to collapse.

Incidence. Young adults 18–25 years of age are most commonly affected, although older persons with asthma or chronic obstructive pulmonary disease are also susceptible.

Symptoms include chest pain, cough, and dyspnea and range from mild to severe.

Diagnosis is made by physical examination and chest radiograph.

Treatment is achieved by chest tube drainage of the pleural space.

Indications for surgery

Recurrent pneumothorax (ipsilateral or contralateral)

Persistent air leak for 3–5 days

Incomplete lung expansion

Hemopneumothorax

Procedure is stapling of apical blebs and pleural abrasion. This is an excellent indication for videothoracoscopy and repair.

B Pleural effusions

Transudative effusions result from systemic disorders that alter hydrostatic or oncotic pressures, allowing the accumulation of protein-poor plasma filtrate in the pleural space.

Treatment is directed toward the underlying systemic process. Thoracentesis may be helpful for both

diagnosis and symptomatic relief. Tube thoracotomy should be avoided if possible.

Exudative effusions result from the local pleural pathology, which alters the permeability characteristics of the pleura, allowing accumulation of a protein-rich plasma filtrate within the pleural space.

Treatment usually requires tube thoracostomy, videothoracoscopy, or thoracotomy to resolve effusion.

C Pleural empyema

Pus in the pleural space usually accumulates secondary to pulmonary infection.

Pathophysiology of empyema evolves in three stages.

Acute or serous phase (onset to 7 days) during which pleural fluid is initially produced

Transitional or fibrinopurulent phase (7–21 days) during which fluid gravitates to dependent areas and undergoes septation and loculation

Chronic or organized phase (>21 days) in which fibrin and pleura fuse and thicken around the periphery of the fluid, resulting in frank abscess formation

Diagnosis is made by thoracentesis in a patient with pleural effusion and fever.

The aspirated fluid is sent for laboratory studies. If organisms are seen on a Gram stain, if organisms are cultured out, or if the pH is below 7.4, the diagnosis is probably an empyema.

On gross examination, if the fluid is very cloudy or smells foul, an empyema is likely to be present.

Treatment

Early empyemas associated with pneumococcal pneumonia may be treated with repeated aspiration and antibiotics.

P.108

Established empyemas , which usually have thicker fluid, need continuous closed drainage. If the empyema is loculated and, therefore, not completely drained by the intercostal tube, then thoracotomy, debridement, and decortication are necessary.

Small, dependent empyemas that do not respond to chest tube drainage may require open drainage via localized rib resection, especially in poor -risk patients.

Recent use of computed tomography (CT)–guided catheters followed by pleural lytic therapy using TPA has demonstrated impressive results in successfully draining empyemas and avoiding surgical intervention.

D Pleural tumors and mesothelioma

Localized benign mesotheliomas are not related to asbestos exposure. They usually arise from the visceral pleura and are treated by local excision.

Malignant mesothelioma is related to prior asbestos exposure, arises in the parietal pleura, and presents with a pleural effusion. It is almost always a fatal disease. The role of surgery is primarily for diagnosis and palliation of symptomatic malignant effusion—usually by way of thoracoscopy and talc sclerosis.

Chemotherapeutic agents are used to treat this disease. Fewer than 5% of patients require pulmonary resection as part of their therapeutic regimen, and this is usually performed after a course of chemotherapy.

Indications for surgery

Bronchopleural fistula with empyema

Destroyed lobe or lung

Persistent open cavities with positive sputum

Post -tubercular bronchial stenosis

Pulmonary hemorrhage

Suspected carcinoma

Aspergilloma

Bronchiectasis

IV Solitary Pulmonary Nodules (Coin Lesions)

Solitary pulmonary nodules are well-circumscribed, peripheral nodules that are manifestations of neoplastic disease (e.g., bronchogenic carcinoma) or of granulomatous or infectious processes (e.g., fungus or tuberculosis).

A General characteristics

Solitary pulmonary nodules are usually asymptomatic.

They occur more often in men than in women.

B Benign versus malignant etiology

When no other tumor is known to be present, the solitary pulmonary nodule is rarely a sign of metastatic disease.

If the patient is younger than 40 years of age, there is a two-thirds chance that the lesion is benign.

The likelihood of cancer is higher in men than in women.

Radiographic evidence of a benign lesion includes the following:

Calcification is present, particularly concentric, heavy, or popcornlike calcification (if the calcification appears as small flecks, a malignant lesion should be suspected).

Radiographs taken at least 2 years apart show no growth in the size of the lesion.

The lesion's size is less than 1 cm in diameter. (The larger the lesion, the greater is the chance of a malignancy.)

CT scan demonstrates a well-circumscribed lesion. (Multiple lesions that are demonstrated on a CT scan but are not seen on plain film suggest either metastatic disease or satellite lesions from

carcinoma or granulomas.) There is no advantage of MRI over a CT scan for imaging of solitary pulmonary nodes.

Because no radiographic characteristic other than dense calcification absolutely indicates a benign lesion, tissue biopsy is mandatory for diagnosis.

V Bronchogenic Carcinoma

AOverview

Incidence

Bronchogenic carcinoma is the leading cause of cancer death in the United States.

Approximately 180,000 new cases are diagnosed each year in the United States.

About 95% of lung cancers occur in patients who are older than 40 years of age.

Etiology

Ninety-five percent of all lung carcinomas are related to smoking; affected individuals usually have a history of smoking one or more packs of cigarettes daily for 20 years.

P.110

There is no known environmental cause. However, chronic exposure to various substances may play a role; nickel, asbestos, arsenic, radioactive materials, and petroleum products have all been implicated.

B Pathology

Adenocarcinoma is now the most common lung carcinoma , representing 30%–45% of all malignant lung cancers. It is less strongly associated with smoking and occurs more commonly in women.

Histology reveals distinct acinar formation of cells, which arise from the subsegmental airways in the periphery of the lung.

Characteristics

Many of these tumors are formed in conjunction with lung scars, representing a response to chronic irritation.

Growth may be slow, but the cancer metastasizes readily by a vascular route. It may spread diffusely throughout the lung via the tracheobronchial tree.

Variants. Bronchoalveolar carcinoma is a variant of adenocarcinoma, which represents a highly differentiated form that spreads along alveolar walls.

Its three forms consist of a solitary nodule, a multinodular form, and a diffuse/pneumonic form.

It has the best prognosis of all the cell types.

Squamous cell carcinoma is the second most common carcinoma of the lung, representing 25%–40% of all malignant tumors. It is associated with smoking.

Pulmonary symptoms include cough, dyspnea, chest pain, fever, sputum production, and wheezing. Patients may be asymptomatic, which is the only clue to the cancer producing an abnormal chest radiograph.

P.111

Extrapulmonary symptoms

Metastatic extrapulmonary manifestations include weight loss, malaise, symptoms referable to the central nervous system, and bone pain.

Nonmetastatic extrapulmonary manifestations (paraneoplastic syndromes) are secondary to hormonelike substances that are elaborated by the tumor. These include Cushing's syndrome, hypercalcemia, myasthenic neuropathies, hypertrophic osteoarthropathies, and gynecomastia.

Pancoast's tumor, which involves the superior sulcus, may produce symptoms related to brachial plexus involvement, sympathetic ganglia involvement, or vertebral collapse secondary to local invasion. This may result in pain or weakness of the arm, edema, or Horner's syndrome (i.e., ptosis, miosis, enophthalmos, and anhidrosis).

D Diagnosis and staging

Abnormal chest radiograph is the most common finding.

The tumor may present as a nodule, an infiltrate, or as atelectasis.

An abnormal chest radiograph is more likely to represent carcinoma in patients older than 40 years of age.

CT scan reveals the extent of the tumor and the possibility of mediastinal lymph node metastasis.

Positron emission tomography (PET) scan is routinely used to assess the primary tumor, the mediastinal lymph nodes, and to screen for metastatic disease.

Bronchoscopy assesses for bronchial involvement and resectability in central lesions, and tissue is obtained for cytologic examination.

Mediastinoscopy or mediastinotomy obtains mediastinal lymph nodes for pathologic examination and aids in the staging of the disease. Positive findings may or may not preclude a curative resection, depending on the pathologic cell type, the extent of nodal involvement, and the condition of the patient.

Percutaneous needle biopsy may be used for peripheral lesions to obtain tissue for cytologic examination.

E

Staging of lung carcinoma is fundamental for the evaluation of treatment protocols (Table 5-1). It is based on information obtained during the preoperative evaluation, findings at mediastinoscopy (see V D 4), thoracotomy, and pathologic findings of the surgical specimens. Definitions of tumor size (T), lymph node metastasis (N), and distant metastasis (M) comprise the TNM classification of carcinoma of the lung by the revised International Clinical Staging System.

TABLE 5-1 Stage Grouping in Cancer of the Lung

T, tumor size; N, lymph node metastasis; M, distant metastasis.

Reprinted with permission from the American Joint Committee for Cancer Staging (AJCC), 1998.

P.112

T (primary tumors)

TX: The tumor is proved by the presence of malignant cells in bronchopulmonary secretions but is not visualized on a radiograph or by bronchoscopy, or any tumor that cannot be assessed, such as one in a retreatment staging.

T0: No evidence of primary tumor

TIS: Carcinoma in situ

T1: A tumor that is 3 cm or less in greatest dimension, surrounded by lung or visceral pleura and with no evidence of invasion proximal to a lobar bronchus at bronchoscopy

T2: A tumor more than 3 cm in greatest dimension or a tumor of any size that either invades the visceral pleura or has associated atelectasis or obstructive pneumonitis that extends to the hilar region. At bronchoscopy, the proximal extent of demonstrable tumor must be within a lobar bronchus or at least 2 cm distal to the carina. Any associated atelectasis or obstructive pneumonitis must involve less than an entire lung.

T3: A tumor of any size with direct extension into the chest wall (including superior sulcus tumors), diaphragm, mediastinal pleura, or pericardium without involving the heart, great vessels, trachea, esophagus, or vertebral body or a tumor in the main bronchus within 2 cm of the carina without involving the carina

T4: A tumor of any size with invasion of the mediastinum or involving the heart, great vessels, trachea, esophagus, vertebral body, or carina or the presence of malignant pleural effusion. In addition, satellite tumor nodules can occur within the ipsilateral primary tumor lobe of the lung.

N (nodal involvement)

N0: No demonstrable metastasis to regional lymph nodes

N1: Metastasis to lymph nodes in the peribronchial or the ipsilateral hilar region, or both, including direct extension

N2: Metastasis to ipsilateral mediastinal lymph nodes and subcarinal lymph nodes

N3: Metastasis to contralateral mediastinal lymph nodes, contralateral hilar lymph nodes, ipsilateral or contralateral scalene or supraclavicular lymph nodes

M (distant metastasis)

M0: No (known) distant metastasis

M1: Distant metastasis present or separate metastatic tumor nodules in the ipsilateral nonprimary tumor lobes of the lung.

F Treatment

Surgical treatment

Pulmonary resection (i.e., lobectomy, extended lobectomy, or pneumonectomy) is the only potential cure for bronchogenic carcinoma. The surgical approach is to resect the involved lung, regional lymph nodes, and involved contiguous structures, if necessary.

Lobectomy is used in disease localized to one lobe.

Extended resections and pneumonectomy are used when the tumor involves a fissure or is close to the pulmonary hilus.

Wedge resections or bronchial segmentectomy may be used in localized disease in high-risk patients.

Contraindications for thoracotomy. One half of all patients with lung carcinomas are not candidates for thoracotomy at the time of diagnosis.

Extensive ipsilateral mediastinal lymph node involvement (N2 disease), particularly high paratracheal and subcarinal

Any contralateral mediastinal lymph node involvement (N3 disease)

Distant metastases

Malignant pleural effusion

Superior vena cava syndrome

Recurrent laryngeal nerve involvement

Phrenic nerve paralysis

Poor pulmonary function (relative contraindication)

P.113

Adjuvant therapy. Further treatment using radiotherapy, chemotherapy, or both is indicated for some advanced -stage tumors.

Postoperative adjuvant chemotherapy is now indicated in all resected nonsmall cell lung cancer patients Stage Ib and higher, demonstrating a small but statistically significant survival benefit.

Preoperative chemotherapy (with or without radiation therapy) in patients with stage IIIa (N2) disease has been used in an attempt to convert advanced local disease into a resectable lesion. However, the efficacy of this therapy has yet to be determined, although early results appear promising.

G

Prognosis depends primarily on cell types and on the stage of disease at the time of diagnosis.

Five-year survival based on cell type

Bronchoalveolar carcinoma, 30%–35%

Squamous cell carcinoma, 8%–16%

Adenocarcinoma, 5%–10%

Small cell carcinoma, <3%

Five-year survival based on postoperative pathologic stage

Stage I, 60%–80%

Stage II, 40%–55%

Stage IIIa, 10%–35%

VI Bronchial Adenomas

The term adenoma is an unfortunate misnomer because these lesions are all malignant neoplasms, albeit relatively low grade in character. They arise from the epithelium, ducts, and glands of the tracheobronchial tree and include the carcinoid tumor, adenoid cystic carcinoma (cylindroma), and mucoepidermoid carcinoma.

A

Carcinoid tumors which comprise 80%–90% of bronchial adenomas, occur mainly in the proximal bronchi (20% main stem bronchi, 60% lobar or segmental bronchi, and 20% peripheral parenchyma).

Characteristics

Characteristics

The location and distribution in the tracheobronchial tree are similar to those found with carcinoid tumors

High-grade and low -grade variants exist, although the latter type predominates.

Treatment principles that are outlined for carcinoid tumors apply to low -grade mucoepidermoid carcinoma. High-grade variants should be approached and managed like other bronchial carcinomas.

VII Hamartomas

A Pathology

These pulmonary tumors are benign and are classified histologically as adenochondromas. They occur within the substance of the lung and usually present as solitary pulmonary nodules.

B

Treatment involves removal during a diagnostic thoracotomy for evaluation of the solitary nodule.

VIII Metastatic Tumor

A

Metastatic tumors are common to the lung, which may be the only site of metastases from a nonpulmonary primary tumor.

B Treatment

Single or multiple metastatic tumors can be removed from the lung as part of the treatment protocol (Table 5-2).

The best treatment results are obtained with metastatic tumors that can be completely resected and in those patients with less than three to five metastatic nodules.

TABLE 5-2 Common Metastatic Pulmonary Tumors

P.115

IX Disorders of the Trachea

AAnatomy

Structure

The trachea is 11 cm from the cricoid to the carina with a range in the adult of about 10–13 cm in length and 1.8–2.3 cm in diameter.

The trachea is encircled by 18–22 cartilaginous rings. The cricoid cartilage is the only complete tracheal ring. The remaining rings are incomplete and have a membranous portion posteriorly.

The trachea is vertically mobile. When the neck is extended, one half of the trachea is in the neck; when the neck is flexed, the entire trachea is behind the sternum.

Relationship to other organs

The thyroid isthmus is at the second or third tracheal ring.

The innominate artery crosses the trachea in its midportion.

The aorta arches over the trachea in its distal portion.

The esophagus is posterior to the trachea throughout its course.

Blood supply is segmental and is shared with the esophagus. Blood is supplied by the inferior thyroid artery, the subclavian artery, the superior intercostal artery, the internal mammary artery, the innominate artery, and the bronchial circulation.

B Congenital lesions

Types

Stenosis. The three types of tracheal stenosis are generalized, funnel, and segmental. The bronchi may be small in congenital tracheal stenosis, and an associated pulmonary artery sling, in which the artery tethers the trachea, may be present. Webs may also be present.

Congenital tracheomalacia. Cartilaginous softening is caused by compression of the trachea by vascular rings, which are anomalies of the aortic arch. These anomalies include a double aortic arch, a right arch with a left ligamentum arteriosum, an aberrant subclavian artery, or an aberrant innominate artery. The diameter of the trachea is normal, but the wall is collapsible.

Diagnosis

Signs and symptoms

Inspiratory and expiratory wheezing, or stridor, which may be paroxysmal

Feeding problems

Frequent infections

Diagnostic studies

Air tracheography (tomography)

Bronchoscopy

Angiography to assess vascular anomalies

Treatment

Stenosis and webs are usually treated conservatively because of the difficulty in performing tracheal reconstruction in infants.

A web may be removed endoscopically.

Tracheostomy may be helpful and should be performed in a narrow area to avoid injury to normal parts of the trachea.

Chondromalacia is treated by aortopexy and is performed under bronchoscopic guidance to maximize the tracheal lumen. The patient may still have some airway problems for a period of time postoperatively.

C Neoplasms of the trachea

Types

Primary neoplasms are rare.

Squamous cell carcinomas are the most common neoplasms of the trachea. They may be exophytic, may cause superficial ulceration, or may be multiple lesions with interposed

P.116

areas of normal trachea. The tumor spreads through the regional lymph nodes and by direct extension to mediastinal structures.

Adenoid carcinoma grows slowly and has a prolonged course.

Other primary tracheal neoplasms include carcinosarcomas, pseudosarcomas, mucoepidermoid carcinomas, squamous papillomas, chondromas, and chondrosarcomas.

Secondary tumors to the trachea are usually from the lung, the esophagus, or the thyroid gland.

Diagnosis

Radiographic studies include a chest radiograph, tracheal tomogram, and fluoroscopy for evaluation of the larynx. Instillation of contrast medium is rarely necessary for the evaluation of tracheal tumors.

Bronchoscopy is deferred until the final operation because the biopsy may be hazardous due to bleeding or obstruction of the airway. Frozen section examination is adequate for assessment of the tracheal tumor.

Pulmonary function testing is mandatory if carinal or pulmonary resection is contemplated.

Treatment is by tracheal resection.

Overview

Preoperative antibiotics are selected on the basis of preoperative tracheal cultures.

When there is an airway obstruction, anesthesia should be induced with halothane.

High-frequency ventilation may be helpful, and it may be possible to pass a small tube beside the tumor.

Seminoma

Embryonal cell carcinoma

Teratocarcinoma

Choriocarcinoma

Endodermal sinus tumor

Symptoms include chest pain, cough, and hoarseness caused by invasion of the vagus nerves.

Diagnosis. These tumors are diagnosed by a combination of radiographs and serum tumor markers

(β-human chorionic gonadotropin and α-fetoprotein)

Treatment

Seminomas are treated by complete surgical resection followed by postoperative radiotherapy.

Nonseminomas are treated by combination chemotherapy.

Adjuvant therapy. Seminomas are very radiosensitive, and the other cell types may benefit from chemotherapeutic agents.

B

Visceral compartment lesions are usually cystic. The two most common types are pericardial cysts and bronchogenic cysts.

Pericardial cysts are usually asymptomatic and are seen on a chest radiograph. They are smooth walled and occur most commonly in the cardiodiaphragmatic angle. Surgery is usually done as a diagnostic procedure to identify the lesion.

Bronchogenic cysts generally arise posterior to the carina. They may be asymptomatic, or they may cause pulmonary compression, which can be life threatening, particularly in infancy. The usual treatment is surgical excision.

Ascending aortic aneurysms are also included as middle mediastinal masses due to the location of the great vessels in this compartment.

C

Paravertebral sulcus lesions are neurogenic tumors located in the paravertebral gutter. Approximately 10%–20% are malignant.

Incidence. Seventy -five percent of these neurogenic tumors occur in children younger than 4 years of age. A malignancy is most likely to occur if the tumor begins during childhood.

Histologic types

Neurilemomas, which arise from the Schwann cells of the nerve sheath

Neurofibromas, which can degenerate into neurosarcomas

Neurosarcomas

Ganglioneuromas, which originate from sympathetic ganglia

Neuroblastomas, which also arise from the sympathetic chain. Neuroblastomas may have metastasized to bone, liver, and regional lymph nodes by the time that the diagnosis is made. Also, direct extension to the spinal cord may occur.

Pheochromocytomas occur in the mediastinum, although rarely; they behave similarly to the usual intra - adrenal pheochromocytomas.

Symptoms

Symptoms include chest pain secondary to compression of an intercostal nerve. If the tumor grows intraspinally, it may cause symptoms of spinal cord compression. Rarely, these tumors have an endocrine function and can secrete catecholamines.

The symptoms of neuroblastoma include fever, vomiting, diarrhea, and cough.

Diagnosis is by chest radiograph and CT scan.

Treatment is by surgical excision. Postoperative radiation is helpful in the treatment of malignant tumors.