T masses continues to evolve as newer imaging modalities

Thoracoscopic Diagnosis and Treatment of Mediastinal Masses John A. Kern, MD, Thomas M. Daniel, MD, Curtis G. Tribble, MD, Mark L. Silen, MD, and Bradley M. Rodgers, MD Divisions of Pediatric and Thoracic Surgery, Department of Surgery, University of Virginia Health Sciences Center, Charlottesville, Virginia Evaluation of mediastinal masses often involves an array of imaging procedures and percutaneous biopsy techniques. Despite this, surgical intervention with an open biopsy is often required, especially to diagnose mediastinal malignancies. We report 22 patients with mediastinal masses who were managed with thoracoscopic biopsy, as opposed to open biopsy. All of these patients either had unsuccessful fine-needle aspiration or were unacceptable candidates for percutaneous aspiration. The patients ranged in age from 11 months to 67 years with a mean age of 17.2 f 3.6 years. Thoracoscopy provided an accurate tissue diagnosis in 19 of the 22 patients (86%) without need for an open diagnostic procedure. In 1 patient, histoplasmosis was suspected from the thoracoscopic biopsy, but open thoracotomy was needed for confirmation. Of the 19 patients with a positive tissue diagnosis, 3 patients had bronchogenic cysts that were completely resected by thoracoscopy. The mean duration of chest tube drainage was 2.3 f 0.2 days, and there were no complications or procedure-related deaths. The average length of hospitalization was 6.0 f 0.8 days. We believe that thoracoscopy is a safe, rapid, and effective modality for the diagnosis of mediastinal masses. Accurate tissue diagnoses are obtained in most patients without the need for additional procedures. In addition, we have demonstrated that complete excision of certain benign lesions during thoracoscopy is possible. (Ann Thorac Surg 1993;56:92-6) he diagnostic approach to patients with mediastinal T masses continues to evolve as newer imaging modalities become available [l]. However, to determine the most appropriate therapy for the individual patient with a newly diagnosed mediastinal mass, accurate histologic classification of the lesion is ultimately required. Although percutaneous fine-needle aspiration is being used more frequently to obtain a cytologic diagnosis with increasing specificity, accurate histologic classification often cannot be made with this technique [2, 31. Although some authors have reported success with large-gauge needle biopsies, many tumors are difficult to differentiate using needle biopsy techniques alone [4]. Often, multiple specimens from the same tumor are required to establish an accurate diagnosis. In addition, needle biopsies may not provide an adequate amount of tissue to allow for immunotyping, which is often essential in the management of patients with malignant lesions [4]. Traditionally, the more invasive procedures that have been used to obtain tissue for the diagnosis and classification of mediastinal lesions include mediastinoscopy, anterior mediastinotomy, median sternotomy, and thoracotomy. Mediastinoscopy is generally only effective for evaluating masses in the peritracheal region and has been associated with substantial morbidity and procedurerelated mortality [5]. In addition, this procedure is not Presented at the Thirty-ninth Annual Meeting of the Southern Thoracic Surgical Association, Wesley Chapel, FL, Nov 5-7, 1992. Address reprint requests to Dr Rodgers, Department of Surgery, University of Virginia Health Sciences Center, Box 181, Charlottesville, VA 22908. suitable for use in small children. Although sternotomy and thoracotomy are both effective for thoroughly evaluating the pathologic anatomy and obtaining adequate tissue for establishing a diagnosis, these open procedures also carry substantial morbidity and mortality. Anterior mediastinotomy, the Chamberlain procedure, is an operation of lesser morbidity than a thoracotomy, but this technique suffers from the limited exposure that it provides of other areas within the chest, which may also be involved with malignant processes. Because complete surgical excision is not needed for the optimal management of many mediastinal lesions [6], an accurate diagnostic modality short of an open surgical procedure would seem ideal. Since 1981, we have used thoracoscopic biopsy, as opposed to open biopsy, in 22 patients with mediastinal masses. This select group of patients either had nondiagnostic percutaneous needle aspiration or were thought to be unacceptable candidates for percutaneous needle aspiration because of either their age or the location of the lesion. For these same reasons these patients were not considered candidates for mediastinoscopy, and thoracoscopy was chosen as a less morbid diagnostic procedure than open thoracotomy. Material and Methods Twenty-two patients with undiagnosed mediastinal masses have undergone thoracoscopic biopsy and treatment at the University of Virginia Health Sciences Center since July 1981. These patients ranged in age from 11 0 1993 by The Society uf Thordcic Surgeons 0003-4975/93/$6.00

Ann Thorac Surg 1993;5692-6 KERNETAL 93 THORACOSCOPY FOR MEDIASTINAL MASSES months to 67 years (mean age & standard error of the mean, 17.2 * 3.6 years). All patients had undergone frontal and lateral chest radiography during their initial diagnostic evaluation. In addition, all of the patients underwent further imaging studies, including either transthoracic ultrasonography, computed tomography, or magnetic resonance imaging. Seven patients had previously undergone unsuccessful percutaneous needle aspiration of their lesions, whereas 15 patients had lesions that were not ideal for percutaneous aspiration, or they were unacceptable candidates. Twenty of the 22 patients underwent thoracoscopy under general anesthesia, and 2 patients (ages, 14 and 67 years) underwent thoracoscopy under regional anesthesia using intercostal nerve and stellate ganglion blocks. Of the 20 patients receiving general anesthesia, 10 were managed with unilateral ventilation. Twelve patients were approached through the right chest and 10 patients underwent thoracoscopy through the left chest. The details of the technique we employed for thoracoscopy in these patients have been previously described [7]. As a general rule, patients with anterior mediastinal masses were placed in a 45-degree lateral decubitus position, and the initial telescope trocar was placed in the anterior axillary line in the sixth intercostal space. A second trocar was placed more posteriorly in the fourth or fifth intercostal space for retraction of the lung inferiorly and posteriorly. Operating trocars were then placed anteriorly to retract and dissect the lesion. Unilateral ventilation is particularly useful in these patients as it allows for optimal retraction of the lung and facilitates mediastinal exposure and dissection. In patients with posterior mediastinal masses, an exaggerated lateral decubitus position was used and the initial telescope trocar was placed in the posterior axillary line in the sixth or seventh intercostal space. The retracting trocar was placed more anteriorly and the operating trocars were placed in locations that would facilitate the subsequent mediastinal dissection. A rigid 0-degree rod-lens telescope was used in all patients. After placement of all trocars, the pleura overlying the lesion was incised either with the dissecting scissors or with the hook-cautery. The hook-cautery device is ideal for dissecting mediastinal lesions as it allows tenting of the parietal pleura as it is divided. If there was any question of the lesion being cystic or vascular, a long needle was passed through one of the operating trocars and the lesion was aspirated. Aspiration of mucoid material suggested a bronchogenic cyst, and in 3 of our patients (ages, 2, 12, and 32 years) such lesions were completely excised by thoracoscopy. Extensive biopsy of mediastinal lymph nodes and noncystic lesions was performed rather than total excision. Finally, all patients were managed postoperatively with a single chest tube placed under direct visualization through one of the trocar sites for optimal postoperative drainage. A pleural catheter was often employed for postoperative analgesia, using 0.25% bupivicaine with epinephrine (0.75 ml/kg every 4 to 6 hours). Table 1. Mediastinal Tumors Accurately Diagnosed By Thoracoscopy ~. - Number of Diagnosis Patients Ages (y) Benign hyperplastic lymph nodes 4 10, 13, 35, 67 Bronchogenic cyst 4 2, 8, 12, 32 Non-Hodgkin s/hodgkin s lymphoma 3 14, 17, 20 Histoplasmosis 3 11, 13, 14 Granulomatous inflammation 2 5, 58 Normal thymus 2 12, 13 Acute lymphocytic leukemia 1 4 Results Of the 22 patients who underwent thoracoscopic evaluation of mediastinal lesions, 18 were pediatric patients under the age of 18 years. Thoracoscopic biopsy was completed successfully in 21 of the 22 patients in whom the procedure was attempted. In 1 patient, an ll-monthold male infant with a posterior mediastinal mass, an adequate tissue biopsy specimen was not able to be obtained by thoracoscopy because of difficulty in retracting the lung. An open thoracotomy was needed to perform biopsy on enlarged, hyperplastic lymph nodes. This patient was the youngest individual in our series, and unilateral ventilation was not able to be used. Thoracoscopy provided a positive tissue diagnosis in 19 of the 21 patients (90%) in whom tissue biopsy specimens were obtained. In 1 patient with an anterior mediastinal mass, histoplasmosis was suspected from the thoracoscopic biopsy but open thoracotomy was performed for confirmation of the diagnosis. In another patient with an anterior mediastinal lesion, thoracoscopic biopsy revealed no pathologic diagnosis, but based on clinical suspicion an open biopsy was performed through a median sternotomy and a diagnosis of recurrent non-hodgkin s lymphoma was established. Of these 21 patients who successfully underwent thoracoscopic biopsy or resection of mediastinal lesions, 17 had masses of the anterior or middle mediastinum, and 4 clearly had their lesions confined to the posterior mediastinum. The specific diagnoses made in the 19 patients in whom thoracoscopic biopsy was successful are listed in Table 1, and include benign reactive lymph nodes in 4 patients, bronchogenic cysts in 4 patients, non-hodgkin s or Hodgkin s lymphoma in 3 patients, histoplasmosis in 3 patients, granulomatous inflammation in 2 patients, normal thymus in 2 patients, and acute lymphocytic leukemia in 1 patient. In 3 of the 4 patients with bronchogenic cysts, complete cyst excision was successfully performed during the same thoracoscopic procedure. The fourth patient with a bronchogenic cyst was successfully diagnosed by thoracoscopy but required an anterior thoracotomy for complete cyst excision and excision of an associated pulmonary sequestration. Figure 1 shows the posteroanterior and lateral chest radiographs of a 32-year-old woman with an anterior mediastinal mass. This was an asymptomatic patient who

94 KEIWETAL THORACOSCOPY FOR MEDlAbTINAL MASSES Ann Thorac Surg 1993;56:924 underwent routine chest radiography as part of a preoperative evaluation before a gynecologic procedure. She also underwent magnetic resonance imaging for further anatomic definition of the mass before surgical interven- Fig 2. Magnetic resonance imaging study of the same patient as in Figure 1. Useful anatomic information can usually be obtained with computed tomographic or magnetic resonance imaging studies before thoracoscopy. tion (Fig 2). Because this lesion was believed to be a bronchogenic cyst, the patient underwent thoracoscopic evaluation of her mediastinum through her right chest. Complete thoracoscopic excision of a bronchogenic cyst was successfully performed. Her chest tube was removed on postoperative day 3 and she was discharged the following day. She recovered uneventfully. To summarize our results, thoracoscopic biopsy provided an accurate tissue diagnosis, on which optimal treatment was planned, in 19 of the 21 patients (90%) in whom biopsy specimens were actually obtained. Overall, of the 22 patients undergoing attempted thoracoscopic evaluation of mediastinal lesions, 86% (19) were diagnosed successfully without the need for further open surgical procedures and 14% (3) required subsequent thoracotomy or sternotomy to establish a diagnosis. Other than the 3 patients requiring an open surgical procedure, no patient had a complication or death resulting from the thoracoscopies. The mean duration of postoperative chest tube drainage in the 18 patients not requiring open intervention was 2.3 + 0.2 days (range, 0 to 5 days), and the average length of hospitalization was 6.0 0.8 days (range, 2 to 15 days). * Comment B Fig 1. Z osterounterior ( A ) and lateral (B)chest radiographs demonstrating a right-sided anterior superior mediastinal mass in a 32-yearold asymptotizatic woman. Thoracoscopic evaluation of this muss revraled a bronchogenic cyst, -which was conrpletrly excised through the thorucoscope. The clinical presentation of patients with mediastinal masses can vary from no symptoms, to symptoins related to the mass itself, to systemic complaints resulting from a particular neoplasm or infection. A report by Davis and associates [l]stated that approximately 60% of patients with mediastinal masses are symptomatic. Patients with benign lesions tend to be asymptomatic, whereas those with malignant lesions are more likely to present with symptoms referable to their lesion. Although the types of mediastinal lesions diagnosed tend to vary with the age of tend the patient, in genera, anterior to include thymomas, lymphomas! and germ cell tumors, whereas the most frequent lesions Seen in the middle mediastinurn tend to be inflamed nodes and teratomasg

Ann Thorac Surg 1993;56:924 KERNETAL 95 THORACOSCOPY FOR MEDlASTlNAL MASSES bronchogenic and pericardial cysts [l]. Tumors arising in the posterior mediastinum tend to be neurogenic in origin [I]. The diagnostic approach to patients with mediastinal masses usually begins with posteroanterior and lateral chest radiographs. Although it provides no specific diagnostic information, the plain chest radiograph can provide important information concerning the location and size of the lesion, displacement of adjacent structures, and whether or not the lesion is cystic. After the initial plain chest radiograph, a number of imaging modalities are presently available to further delineate the pathologic anatomy: plain radiography, tomography, ultrasonography, angiography, computed tomography, radioisotopic scanning, and magnetic resonance imaging. Merten [8] recently reviewed the diagnostic imaging of mediastinal masses in children and concluded that after the plain chest radiograph, computed tomography is the crosssectional imaging modality of choice in evaluating most mediastinal masses. According to Merten, the exceptions to this rule are the use of magnetic resonance imaging to evaluate posterior mediastinal masses or vascular lesions, and ultrasound for the evaluation of foregut cysts. Indeed, ultrasound can be very sensitive in its detection of mediastinal masses. In a prospective study performed by Wernecke and associates [9], sonography was found to be superior overall to plain chest radiographs in diagnosing mediastinal tumors. In addition, ultrasound was found to be so sensitive in evaluating specific areas of the mediastinum (paratracheal, pericardial, supraaortic) that Wernecke and associates concluded that computed tomography and magnetic resonance examinations were probably not needed in patients with equivocal plain radiographic findings and specific findings on ultrasound. Gallium-67 scans have been reported by some to be very useful in the evaluation and follow-up of patients with malignant lymphoma [lo]. Although modern imaging modalities can provide a great deal of information that is useful in evaluating the patient with a mediastinal mass, optimal treatment depends on the precise histologic evaluation of the lesion. Several authors have recently reported on the utility of needle aspiration of mediastinal masses. Herman and associates [4] reported that in patients with anterior mediastinal masses, transthoracic needle biopsies were greater than 90% specific in diagnosing most tumors, but the sensitivity in diagnosing lymphomas was less than 50%. In addition, thymomas were also less reliably diagnosed using percutaneous needle aspiration. A study by Yu and associates [ll] evaluating ultrasound-guided aspiration and cutting biopsies of mediastinal lesions reported that although needle aspiration biopsy had a high diagnostic yield for most mediastinal tumors, large-bore cutting biopsies were needed for thymic tumors, lymphomas, and benign lesions. In addition, in Yu and associates' study, both aspiration and cutting biopsies together provided an accurate diagnosis in only 78% of benign lesions. Although large-bore cutting biopsies have increased the sensitivity of percutaneous biopsy techniques, the incidence of pneumothorax can be as high as 23% [3] and not all lesions are in locations amenable to percutaneous needle biopsy [12]. The more invasive modalities that are commonly used to obtain adequate tissue for the precise diagnosis of mediastinal masses include mediastinoscopy, anterior mediastinotomy, median sternotomy, and thoracotomy. Mediastinoscopy is relatively minimally invasive, but lesions must be located in the paratracheal region to be accessible by this method, and this technique is not an option in young children because of the narrow thoracic inlet. In addition, in centers where this technique is not commonly used, morbidity and major hemorrhage rates are as high as 16% and mortality can be as high as 2% [5]. Although open surgical procedures such as median sternotomy and either anterolateral or posterolateral thoracotomy allow optimal access to thoroughly evaluate most mediastinal masses, these open procedures have small but definite morbidity and mortality rates. In addition, because surgical excision is not necessary for the treatment of all mediastinal lesions, the large incision of a sternotomy or thoracotomy is not always needed. The accurate diagnosis of mediastinal lesions through less invasive modalities such as thoracoscopy would seem ideal. Thoracoscopy is being used by more thoracic surgeons for the diagnosis and treatment of a wide range of intrathoracic diseases. Its use in the diagnosis and treatment of mediastinal masses has not been widely described. In 1981, Rodgers and associates [13] reported on the efficacy of thoracoscopy for the diagnosis and staging of intrathoracic tumors in children and adults. Included in this series were 16 patients with mediastinal masses. Overall, thoracoscopy provided an accurate diagnosis in 92% of the patients, with no clinically significant morbidity and no procedure-related mortality [13]. In addition, 5 of these patients (31%) had areas of unsuspected tumor involvement identified by thoracoscopy because of the ability to examine the entire hemithorax with this technique. In 1989, Mai and associates [14] presented several case reports that demonstrated the efficacy and safety of thoracoscopy in providing accurate diagnoses in patients with mediastinal masses. Our present results are similar to those reported previously by Rodgers and associates and by Mai and associates, and compare favorably with the published reports of percutaneous needle aspiration for the diagnosis of patients with similar mediastinal lesions [3, 4, 121. Thoracoscopy allows direct visualization of the entire pathologic anatomy, and multiple representative biopsy specimens may be obtained. In addition, thoracoscopy is an extremely safe procedure. In the present series, no clinically significant complications were encountered and there were no procedure-related deaths. Finally, although not all mediastinal masses need to be resected for optimal patient management, thoracoscopy does provide the opportunity for complete resection of certain mediastinal lesions. In our series, 2 children and 1 adult with bronchogenic cysts underwent complete resection during the same diagnostic thoracoscopic procedure. The possibility of converting a diagnostic thoracoscopy

96 KERNETAL THORACOSCOPY FOR MEDIASTINAL MASSES Ann Thorac Surg 1993;5692-6 into a therapeutic procedure for the definitive treatment of mediastinal lesions has recently been illustrated by other authors. Landreneau and associates [15] reported a complete thoracoscopic resection of an encapsulated thymoma in an elderly patient who recovered uneventfully. Lewis and associates [16] reported the use of videoassisted thoracoscopy in the resection of two separate mediastinal cysts. One patient had an esophageal cyst and the second patient had a bronchogenic cyst. Independently, these authors concluded that thoracoscopic resection of certain mediastinal lesions can be safely accomplished without the need for median sternotomy or thoracotomy. These authors concluded that postoperative pain was reduced, hospitalization was shortened, and recovery was hastened as a result of the thoracoscopic approach to the resection of the mediastinal lesions. The diagnostic approach to patients with undiagnosed mediastinal masses should include thorough preoperative imaging to detect those patients with clearly benign lesions who do not require biopsy or resection. Older patients with lesions accessible to needle aspiration should undergo this procedure as an initial diagnostic step. Percutaneous techniques have not been as useful in pediatric patients because of the technical difficulties and the higher incidence of lymphomas. We believe that thoracoscopy should be considered as the next procedure for the evaluation of selected patients with mediastinal masses. Biopsy and resection of certain lesions in the anterior and middle mediastinum is quite feasible, and resection of certain posterior mediastinal lesions has been performed. The role of thoracoscopy in management of solid tumors of the posterior mediastinum, most of which are neurogenic in origin, is questionable. The procedure of thoracoscopy is minimally invasive and has a low morbidity and mortality [17]. In the present series, no procedure-related deaths or complications resulted. All areas of the mediastinum can be approached with equal safety and efficacy. Accurate histologic diagnoses can be obtained in the majority of patients without the need for additional procedures. Complete excision of certain benign lesions during the same thoracoscopic procedure is also possible. As with any diagnostic procedure, a negative biopsy must be carefully evaluated in relation to the clinical course of the patient. Further, more invasive, diagnostic procedures may be appropriate, as in 1 of our patients with recurrent mediastinal lymphoma. References 1. Davis RD Jr, Oldham HN Jr, Sabiston DC Jr. Primary cysts and neoplasms of the mediastinum: recent changes in clinical presentation, methods of diagnosis, management, and results. Ann Thorac Surg 1987;44:229-37. 2. Linder J, Olsen GA, Johnston WW. Fine-needle aspiration biopsy of the mediastinum. Am J Med 1986;81:100.5-8. 3. Moinuddin SM, Lee LH, Montgomery JH. Mediastinal needle biopsy. AJR 1984;143:531-2. 4. Herman SJ, Holub RV, Weisbrod GL, Chamberlain DW. Anterior mediastinal masses: utility of transthoracic needle biopsy. Radiology 1991;180:167-70. 5. Davis RD Jr, Oldham HN Jr, Sabiston DC Jr. The mediastinum. In: Sabiston DC Jr, Spencer FC, eds. Surgery of the chest. Philadelphia: Saunders, 1990:498-534. 6. Haller JA Jr, Mazur DO, Morgan WW Jr. Diagnosis and management of mediastinal masses in children. J Thorac Cardiovasc Surg 1969;58:385-93. 7. Rodgers BM, Talbert JL. Thoracoscopy for diagnosis of intrathoracic lesions in children. J Pediatr Surg 1976;11:703-8. 8. Merten DF. Diagnostic imaging of mediastinal masses in children. AJR 1992;158:825-32. 9. Wernecke K, Vassallo P, Potter R, Luckener HG, Peters PE. Mediastinal tumors: sensitivity of detection with sonography compared with CT and radiography. Radiology 1990;175: 137-43. 10. Weiner M, Leventhal B, Cantor A, et al. Gallium-67 scans as an adjunct to computed tomography scans for the assessment of a residual mediastinal mass in pediatric patients with Hodgkin s disease. Cancer 1991;68:2478-80. 11. Yu CJ, Yang PC, Chang DB, et al. Evaluation of ultrasonically guided biopsies of mediastinal masses. Chest 1991;lOO: 399-405. 12. Wernecke K, Vassallo P, Peters PE, von Bassewitz DB. 16. 17. -, Mediastinal tumors: biousv under US guidance. Radiolow I,., 1989;172:473-6. 13. Rodeers BM. Rvckman FC. Moazam F. Talbert 1L. Thoracos- I, cop; for intrathoracic tumors. Ann Thorac Surg 1981;31: 414-20. 14. Mai J, Loddenkemper R, Brandt HJ. Diagnostic thoracoscopy in mediastinal space-occupying lesions. Pneumologie 1989; 43~122-5. 15. Landreneau RJ, Dowling RD, Castillo WM, Ferson PF. Thoracoscopic resection of an anterior mediastinal tumor. Ann Thorac Surg 1992;54:142-4. Lewis RJ, Caccavale RJ, Sisler GE. Imaged thoracoscopic surgery: a new thoracic technique for resection of mediastinal cysts. Ann Thorac Surg 1992;53:318-20. Weissberg D, Kaufman M. Diagnostic and therapeutic pleuroscopy: experience with 127 patients. Chest 1980;78:732-5.