Retrosternal Goiter

Retrosternal Goiter* Shahar Madjar, MD; and Dov Weissberg, MD, FCCP Background: Retrosternal goiter is a common cause o{ compression of adjacent structures, and it may harbor cancer. Methods: During a 22-year period, we treated 44 patients with intrathoracic multinodular goiter. Results: The goiter was resected in 40 patients; 4 patients were rejected because of prohibitive risk. There were three minor complications and no deaths. Conclusions: The specific indications for resection include compression of adjacent structures, prevention of future complications, and obtaining a diagnosis.

T he definition of retrosternal or intrathoracic goiter is not clearly agreed on. We agree with most authors that a goiter is retrosternal if its greater mass is inferior to the thoracic inlet. 1 However, various different criteria have been suggested by others, 2-6 adding to confusion on a matter of questionable importance. Retrosternal goiter was first described by Haller 7 in 1749. The reported incidence in relation to the number of thyroidectomies ranges from less than 1%3 to more than 20%. 8

Fine-needle aspiration for diagnosis is not always possible and rarely reliable, and there is no effective medical therapy. Cervical incision is nearly always adequate, with few exceptions, such as very large posterior goiter, mediastinal blood supply, or carcinoma necessitating mediastinal dissection. (CHEST 1995; 108:78-82) Key words: intrathoracic goiter; retrosternal goiter; substernal goiter

and posterolateral thoracotomy was performed in two with posterior retroesophageal goiter. Four patients were not operated on because of prohibitive risk. In these patients, diagnosis of colloid goiter was established by needle biopsy specimen. RESULTS

Three patients had complications. Hematoma oc-

METHODS

Between August 1971 and December 1993, 222 patients were referred to our service for thyroidectomy. Of this group, 44 patients had retrosternal goiter, for an incidence of 19.8%. This relatively high incidence is related to the peculiar pattern of patient referral. As the only thoracic-oriented general surgery service in this geographic area, we are receiving a relatively large proportion of patients with intrathoracic goiters, including some from outside of the area served routinely by this medical center. In contrast, patients with cervical goiters and indication for thyroidectomy are distributed randomly among several surgical and head-and-neck services, not necessarily referred to ours. There were 24 men and 20 women, ranging in age from 57 to 84 years (mean, 69 years). All patients were symptomatic: cervical or thoracic mass was present in 33 instances, exertional dyspnea in 22, dyspnea at rest in 12, tracheal deviation in 11, dysphagia in 10, hoarseness in 10, stridor in 7, cough in 5, congested veins in 4, and upper back pain in l. Compression of the trachea occurred in 34 patients (Fig 1), of the esophagus in 11 (Fig 2), and of the superior vena cava in 5 (Fig 3). Only five patients had no evidence of compression of adjacent structures. The goiter was anterior in 39 patients, posterior in 5 (retrotracheal in 3 and retroesophageal in 2). Forty patients were operated on. Standard collar incision was used in all instances. In addition, partial sternotomy was performed in four patients because of a very large retrosternal mass, *From the Department of Surgery, Tel Aviv University Sackler School of Medicine, and the Edith Wolfson Medical Center, Holon, Israel. Manuscript received August 29, 1994; revision accepted September 27.

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FIGURE l. Linear tomography showing compression and deviation of the trachea at the thoracic inlet. Clinical Investigations

died of causes not related to their goiter; the deaths occurred from 2 to 16 years after their operations. Thirty-three patients are well, with follow -up ranging from 1 to 21 years. Six patients were unavailable for follow-up after periods ranging from 1 to 3 years. This includes the four patients who were not operated on and who probably are not alive. The other two patients were unavailable for follow-up, but were in excellent condition when last seen.

Illustrative Cases

2. Both the esophagus and the trachea are pushed anteriorly, away from the spine, in this patient with retroesophageal goiter. FIGURE

curred in two instances and had to be evacuated. No bleeding vessels were found, and the bleeding did not recur. One patient with a large goiter compressing the trachea had a transient vocal cord paresis. There were no deaths related to the operation. Five patients

Patient 1: A 69-year-old woman with history of bronchial asthma, bronchiectasis of the right upper lobe, and hypertensive cardiovascular disease noted progressive increase in shortness of breath over the past 6 months. At the time of hospital admission, she was in moderate respiratory distress. A firm mass was palpated in the neck, mostly on the left side, suggestive of a nodular goiter. The trachea was deviated toward the right side. Chest radiograph showed marked widening of the mediastinum. Computed tomography demonstrated a mass 14 em X 7 em X 5 em, continuous with the left thyroid lobe, compressing the trachea on the left side and ending posteriorly, between the trachea and the esophagus (Fig 4). On surgical exploration through the collar incision, a cyst, 6em in diameter, containing colloid was found in the right thyroid lobe. A large mass continuous with the left lobe was palpated down the thoracic inlet. The lower end of the mass could not be reached, and for a complete and safe delivery, a partial sternal split had to be performed. The entire left thyroid lobe and part of the right lobe, including the colloid cyst, were resected. Histologic examination confirmed colloid goiter. The postoperative course was uneventful, with complete subsidence of the dyspnea. At the 1 year follow-up, the patient is

FIGURE 3. Superior vena cava syndrome caused by colloid goiter in a 63-year-old woman. The mass was resected through a sternum-splitting incision, with complete subsidence of symptoms.

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DISCUSSION

FIGURE 4. Tracheal bifurcation pushed away from the spine by a posteriorly located mass. Another mass is seen behind the sternum. Both masses were continuous on the left side of the trachea. Bronchiectatic changes are seen in the right upper lobe.

well. Patient 2: A 68-year-old woman (originally described in a case report 9) complained of increasing upper back pain for 1 month . A 10-cm mass was palpated in the right thyroid lobe. It had been present for nearly 40 years and was of no concern to the patient. There were no symptoms of airway obstruction or dysphagia. Chest radiographs showed a superior mediastinal mass on the right side. The Iodine-131 thyroid scan demonstrated an enlarged right thyroid lobe with normal activity. The mediastinal mass absorbed iodine and appeared continuous with the enlarged thyroid lobe. Esophagogram showed displacement of the esophagus anteriorly and toward the right side. Surgical exploration of the neck revealed a globe-shaped right thyroid lobe 10 em in diameter. It did not extend into the chest. The left thyroid lobe appeared normal. Right thyroid lobectomy was performed. The postoperative radiographs were identical with the preoperative ones, with the mediastinal mass unchanged. Three weeks after the first operation , right thoracotomy was performed. An 8-cm encapsulated soft mass was found in the superior mediastinum, with the superior vena cava and the azygos vein stretched over it. The mass was dissected and traced behind the esophagus to the thoracic outlet on the left side, where it was continuous with the lower pole of the left lobe. The mass was transsected at the thoracic outlet and removed . Histologic examination of both resected specimens showed nodular goiter. Twelve years later, the patient was asymptomatic and euthyroid, with normal chest radiographs.

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Intrathoracic or retrosternal goiters often are classified into two groups. One is the truly intrathoracic or aberrant goiter. Its presence in the mediastinum is congenital, with the blood supply derived entirely from intrathoracic vessels, and it has no direct connection to the cervical thyroid gland. This group represents less than 1% of surgically removed goiters.l0-13 The much more common second group represents the acquired retrosternal goiter. It arises in the cervical thyroid gland and, while growing, descends along a fascial plane, through the thoracic inlet into the mediastinum. 1·3·6·13·14 Lahey and Swinton 8 described the anatomic factors responsible for that descent. Most intrathoracic goiters are located anteriorly, in front of the subclavian and innominate vessels.' 5-18 Posterior mediastinal goiters with a retrotracheal component constitute 10% to 15% of all intrathoracic goiters; 13·15·19·20 posterior goiters with retroesophageal extension to the contralateral hemithorax have been reported rarely.9·21 Two such patients are included in this series. The most important and urgent indication for resection of a goiter is compression of the adjacent organs: the trachea, the esophagus, and the superior vena cava, usually at the level of the thoracic inlet. This complication is caused by the progressive nature of the disease, combined with the narrow passage at the inlet. However, a very large thyroid mass may cause such compression at a lower level as well. Com pression of the trachea is reported most commonly and occurred in 34 of our patients (77.3%), causing in some of them severe respiratory compromise. Compression or deviation of the esophagus is less common, 25% in this series, although reported at 70% by Michel and Bradpiece. 22 Obstruction of the superior vena cava is uncommon and is associated with malignancy in 75% of instances. 23 Superior vena cava syndrome in association with a benign thyroid mass has been reported infrequently.23-26 However, five such patients are included in this series (11.4%), all with colloid goiter. This is an exceptionally high incidence of this complication, although similar high incidence was reported by Allo and Thompson, 27 who observed this phenomenon in 5 of their 50 patients. Most authors agree that this complication is an absolute indication for operation. 25 ·27 ·28 When obvious signs of compression are not present, resection is indicated for prevention of their possible appearance in the future. This is likely to occur in view of the progressive nature of the disease. Establishing the diagnosis provides another important indication for resection . Contrary to the effec-

Clinical Investigations

tiveness of fine-needle aspiration in diagnosing cervical thyroid nodules, needle biopsy of intrathoracic goiters is frequently unsuccessful. 29 In addition, tissue diagnosis obtained from any part of the goiter is not necessarily representative of the entire gland, which is often inaccessible for a biopsy. Cases abound in which a small carcinoma was permitted to grow in a remote part of the multinodular goiter, after an easily accessible nodule was diagnosed as benign. Therefore, resection is always indicated, and, excepting patients at prohibitive risk, should be performed early. Over 90% of retrosternal goiters can be resected using the standard collar incision. When difficulties arise due to a very large size of the mass, preliminary ligation of the thyroid vessels enables resection of virtually all goiters located anteriorly. The morcellation technique described by Lahey 14 helps to avoid splitting of the sternum. However, upper midline sternotomy in addition to the collar incision is safer for posterior retrotracheal goiters, particularly when the lower pole of the gland cannot be reached from the neck. 22 Of course, any mediastinal goiter separate from the cervical thyroid has mediastinal blood supply and must be resected through a sternotomy incision. Attempts at resection through a collar incision are hazardous and can result in uncontrollable bleeding. Other indications for sternotomy include recurrent intrathoracic goiter, emergency surgery for airway obstruction, and low-lying carcinoma with cervical lymph node involvement. 30 We and others4·31 have used posterolateral thoracotomy for retroesophageal goiters and for undiagnosed thyroid masses. It is important to define the exact topography of any goiter before operation. As pointed out by Ribet 32 and exemplified by our patient (case 2), it can happen that the larger cervical lobe does not descend into the thorax, while the contralateral, apparently normal lobe does, and the initial resection is therefore performed on the wrong lobe. For very large posterior goiters, the combination of thoracic and cervical approaches is probably safest. It was described by Hart in 1950. 21 ·33 In this approach, the thoracotomy is performed as the first step. Intrathoracic blood supply, if present, is secured. If the blood supply is wholly intrathoracic, the mass is removed. If the tumor is fixed at the thoracic inlet, the cervical incision is performed next. It permits dislocation of the mediastinal mass into the neck, ligation of the cervical blood supply, and removal of the tumor from above. We conclude that resection of an intrathoracic goiter is always indicated and should be performed early, except in presence of compelling contraindi-

cations. The specific indications for resection include compression of adjacent structures, prevention of future complications, and obtaining a diagnosis. Fine-needle aspiration for diagnosis is not always possible and rarely reliable, and there is no effective medical therapy. Cervical incision is nearly always adequate, with few exceptions, such as very large posterior goiter, mediastinal blood supply, or carcinoma necessitating mediastinal dissection. REFERENCES

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Clinical Investigations