Mediastinal Granuloma Associated with Pericardi t is Frederic F. Primich, M.D.,* and Herbert C. Maier, M.D. M ediastinal granulomas may be caused by an inflammatory process developing primarily in a group of lymph nodes or may be secondary to an infection in the lungs, pleura, or pericardium. Rarely, a granuloma may result from secondary infection of a mediastinal cyst. Factors in the route of lymphatic drainage may determine the most likely site of lymphadenopathy and possible granuloma formation. If the primary lesion initiating the chronic inflammatory process is within the lung, the hilar and lateral mediastinal nodes, such as the paratracheal group, are most likely to be involved. When the primary inflammatory process is within the pericardium, that group of lymph nodes which drains the lymph from the heart and pericardium is most likely to be affected. Since some of this group of lymph nodes lie deeply imbedded in the midportion of the mediastinum, a granulomatous process resulting from the necrosis and partial liquefaction of these nodes may result in the development of a mediastinal granulomatous mass in an uncommon location. The treatment of such a lesion may present special diagnostic and therapeutic problems. The case herewith reported is that of a granulomatous mass occurring in intimate relationship with the great vessels in the mediastinum which became manifest following pericarditis. The importance of differentiating such a case from the vast majority of other mediastinal granulomatous masses lies in the recognition that such a patient requires a different surgical approach if undue operative hazard is to be avoided. One of the lymph node groups draining lymph from the heart and pericardium lies behind the thymus medial to the ascending aorta and in relation to the right pulmonary artery. If these nodes become involved in an extensive granulomatous process, with central liquefaction and perinodal inflammatory infiltration, the inflammatory reaction is very likely to become intimately associated with the walls of those portions of the aorta and pulmonary artery which are in close proximity. Therefore, the most direct surgical approach that permits good visual- From the Chest Surgical Service of Bellevue Hospital and the Department of Surgery, Columbia University, College of Physicians and Surgeons, New York, N.Y. *Saint Elizabeth Hospital, Elizabeth, N.J. Address reprint requests to Dr. Maier, 3 East 71st St., New York, N.Y. Accepted for publication Jan. 5, 1968. 464 THE ANNALS OF THORACIC SURGERY
CASE REPORT: Mediastinal Granuloma ization of the area is indicated in order to avoid injury to these large vessels which may be closely incorporated in the peripheral parts of the granulomatous mass. Whereas a lateral transpleural approach is usually used for the removal of most mediastinal granulomas which warrant surgical intervention, a large granulomatous mass of the cardiac and pericardial lymph node group can most safely be exposed through a sternotomy incision. Even though it has been amply demonstrated that such granulomatous masses do not have to be completely excised in order to obtain a good clinical result, poor exposure may still increase the hazard of operation because the distinction between the outer limits of the granuloma and the adjacent great vessels may be quite obscure. If there is little perinodal fibrosis where the inflammatory process is in proximity with the aorta and pulmonary artery, a lesser hazard exists. It is fully recognized that only selected cases of granuloma in any portion of the mediastinum may warrant surgical therapy; antibiotic treatment and chemotherapy may produce subsidence of the chronic granulomatous process. Partial necrosis of the granulomatous mass, however, may lead to chronicity, with the development of a fibrous mediastinitis and possible perforation into adjacent structures. Moreover, in a significant number of cases, surgical intervention may be advisable because the diagnosis of neoplasm cannot be ruled out. A 26 year-old Negro male heroin addict was admitted to Bellevue Hospital with a 3-week history of anterior chest pain and x-ray evidence of an anterior mediastinal mass. The chest discomfort was described as dull, intermittent, and usually substernal. It was more marked in the supine or lateral recumbent positions. The patient was relatively comfortable when prone or sitting. He also complained of poor appetite, nausea, and weight loss; these symptoms were attributed to the drug addiction. Eight months before admission the patient was hospitalized elsewhere with a diagnosis of idiopathic pericarditis. At that time he complained of chills and fever. Symptoms were heralded by severe pressing pain in the anterior aspect of the chest. There was a 10-pound weight loss. An enlarged area of cardiac dullness, a palpable liver, and a right supraclavicular lymph node 1 cm. in size were noted. Chest films suggested the presence of pericardial effusion (Fig. 1). Liver biopsy showed sinusoidal congestion, and biopsy of the right supraclavicular node revealed nonspecific hyperplasia. The patient improved with aspirin and Terramycin (oxytetracycline) therapy. The patient s past history revealed periodic attacks of asthma since the age of 2, Osgood-Schlatter s disease at age 13, and heroin addiction for the past 11 years. There was no history of chest trauma. The patient s brother had recently been treated for tuberculosis. Admission physical examination was unremarkable. Chest films revealed an anterior mediastinal density (Fig. 2). The Venereal Disease Research Laboratories test was weakly positive, while the Kolmer test was positive 1:8. The hematocrit was 40%; the white blood count was 4,800, with a normal differential. Histoplasmin and coccidioidin skin tests were negative. Intermediate PPD was positive. Sputum and gastric examinations were consistently negative for tuberculosis. Venous angiography revealed displacement of the main pulmonary artery toward the left and an increase in the distance between the pulmonary artery and VOL. 5, NO. 5, MAY, 1968 465
PRIMICH AND MAIER FIG. 1. X-ray at time of pericardial effusion. adjacent vessels suggestive of a nonvascular mass in the supracardiac portion of the mediastinum. Following admission the patient received a two-week course of penicillin therapy. Since tuberculous pericarditis associated with lymphadenopathy was suspected, isoniazid and aminosalicylic acid therapy were also started. However, after 6% weeks of therapy with no definite radiographic change, surgery was advised. The anterior mediastinum was explored via a median sternotomy approach. A smooth-walled mass was noted immediately deep to the thymus. It was readily evident that the lesion could not be safely excised in toto. After exploratory aspiration of the central part of the mass, incision revealed a thick-walled cystic A FZG. 2. (A) Posteroanterior x-ray showing regression of pericardial effusion and suggestion of mass in supracardiac region. (B) Lateral x-ray showing anterior mediastinal mass in supracardiac region. B 466 THE ANNALS OF THORACIC SURGERY
CASE REPORT: Mediastinal Granuloma cavity containing approximately 200 ml. of viscid material with fragments of anthracotic debris. The cavity was unroofed, thoroughly irrigated with saline solution, and debrided of necrotic tissue. The anthracotic fragments resembled broken-down lymph nodes. The ascending aorta and right pulmonary artery had been separated somewhat by the cystic mass. Although considered, biopsy of the pericardial sac was not performed in order to avoid unnecessary contamination of the pericardial space. A soft-rubber drain was placed into the involved area and brought out below the reconstructed sternum. The wound was closed primarily. Microscopic examination of the excised tissue revealed dense fibrous tissue infiltrated by acute inflammatory cells. Plasma cells were prominent, and an occasional multinucleated giant cell was noted. No acid-fast bacilli were identified. Cultures were negative for tuberculosis. The patient s postoperative course was entirely uneventful, and the drainage site closed promptly. Antituberculosis therapy was continued. DISCUSSION The recent literature suggests a more frequent recognition of mediastinal granulomas. The majority of the reported lesions have been cystic, and have often been located in the right paratracheal region. Other less frequently reported locations include the left paratracheal, subcarinal, and paraesophageal regions [2-41. Frequently, bacteriological studies have failed to demonstrate the etiological agent. Although these granulomas may be found on x-ray examination in an asymptomatic stage, in some cases the lesion may be symptomatic and lead to a localized fibrous mediastinitis. The signs and symptoms which then develop will be largely dependent on the location of the granulomatous process. Ferguson and Burford [ 11 have well demonstrated that surgical treatment of these granulomas can be safely performed only if it is realized that total excision of the granulomatous mass, which is often closely adherent to major vessels, is usually unnecessary for a good clinical result. The essential requirement is to remove that necrotic and granulomatous tissue which can be excised without damage to other structures. The low incidence of demonstrable bacteria in most such granulomas at the time of surgical intervention undoubtedly is an important factor in the low complication rate and good late results which can be attained. The sequence of events in our case suggested a mediastinal adenitis associated with a pericarditis, with subsequent development of a sterile cystic granuloma. The lymphatics of the pericardium drain into various mediastinal lymph nodes, some of which are in the preaortic region of the mediastinum and in close relationship to the adjacent great vessels. An inflammatory process in these nodes may involve the wall of the adjacent great vessels and also result in a chronic fibrous mediastinitis. VOL. 5, NO. 5, MAY, 1968 467
PRIMICH AND MAIER When a localized granulomatous process produces a marked fibrous reaction, it is more likely to affect the thinner-walled vessels such as the veins. Superior vena caval obstruction and thrombosis may result as a complication of paratracheal granulomatous lymphadenopathy. When the granuloma is located in the depths of the mediastinum, the pulmonary veins may become constricted with the development of cor pulmonale. In a case reported by Nelson et al. [5] the chronic fibrous process constricted the pulmonary artery and pulmonary veins, and a pericardial effusion was present. Their case illustrates that such a granulomatous mass so located may be of insufficient size to be obvious on the x-ray, especially if a pericardial effusion is also present. When the granulomatous mass is in the posterior mediastinum, involvement of the esophagus, either in the form of partial obstruction or traction diverticuli, may be noted. SUMMARY The diagnostic and therapeutic problems presented by a granulomatous mass in the depths of the anterior and central part of the mediastinum are presented. The unusual location of this granuloma appeared to be due to the process being associated with a pericarditis rather than secondary to pulmonary or pleural lesions. A median sternotomy incision gave a safe approach for partial excision of the cystic granulomatous mass, which was in intimate association with large vessels in the supracardiac region. It might be thought that fear of the postoperative development of osteomyelitis of the sternum would be an argument against employing such a surgical approach. This risk seems to be small if operation is undertaken for a granuloma with little evidence of active bacterial infection provided the drainage tube is not brought out through the split sternum but only below the xiphoid. REFERENCES 1. Ferguson, T. B., and Burford, T. H. Mediastinal granuloma-a 15-year experience. Ann. Thorac. Surg. 1 : 125, 1965. 2. Garamella, J. J., Stutnnan, F. L., Varco, R. L., and Jensen, N. K. Subcarinal mediastinal granulomas causing esophageal obstruction. J. Thorac. Surg. 30:187, 1955. 3. Kunkel, W. M., Clagett, 0. T., and McDonald, J. R. Mediastinal granulomas. J. Thorac. Surg. 27:565, 1954. 4. Moore, T. C. Esophageal obstruction due to mediastinal granuloma. J. Thorac. Surg. 37: 127, 1959. 5. Nelson, W. P., Lundberg, G. D., and Dickerson, R. B. Pulmonary artery obstruction and cor pulmonale due to chronic fibrous mediastinitis. Amer. J. Med. 38:279, 1965. 468 THE ANNALS OF THORACIC SURGERY