Thoracic Duct Cyst of the Mediastinum

Abstract

To the Editor: In their article in the June 1975 issue of Chest, Fromang and co-workers1Fromang DR Seltzer MB Tobias JA Thoracic duct cyst causing mediastinal compression and acute respiratory insufficiency.Chest. 1975; 67: 725-727Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar reported a case of thoracic duct cyst with mediastinal compression and acute respiratory insufficiency. They attributed the acute respiratory obstruction to the increased amount of lymph in the thoracic duct following the ingestion of a very fatty meal.1Fromang DR Seltzer MB Tobias JA Thoracic duct cyst causing mediastinal compression and acute respiratory insufficiency.Chest. 1975; 67: 725-727Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar At the Hospital Colonia in Mexico City, we have recently treated a patient with thoracic duct cyst of the mediastinum, the first case in Mexico. Our case showed an interesting clinical picture where a similar pathogenic mechanism may be invoked. The patient, a 42-year-old man, was admitted because of a three-year history of retrosternal pain which occurred in the immediate postprandial period and was aggravated by the ingestion of an abundant meal or alcohol. Physical examination, blood tests, and the electrocardiogram revealed no abnormalities. A chest x-ray film in the posteroanterior projection, as well as a lateral film and chest laminographic studies, showed no alterations. Barium swallow revealed a forward and leftward displacement of the esophagus (Fig 1), and during this study, an apparent mediastinal mass was observed by fluoroscopic examination. A left oblique film taken immediately showed a small dense shadow behind the heart, which did not reappear in subsequent roentgenograms. An exploratory thoracotomy was then performed, and a yellowish smooth-walled tumor without an identifiable pedicle was found in the posterior mediastinum. The tumor was mistaken to be a soft-tissue neoplasm and was resected. The patient's postoperative course was complicated by chylothorax that was successfully treated by surgical approach after the failure of conservative measures. The resected specimen was described as a cyst measuring 12 × 8 × 3 cm, with a thick wall and a trabeculated internal appearance, and containing fibrinous clots and milky fluid. Microscopically, the wall was constituted of fibrous connective tissue, and the inner surface was covered with macrophages containing fat inclusions. Three months after surgery, the patient was in very good condition, and the preoperative symptoms were gone. The thoracic pain closely related to the ingestion of a meal, as seen in our patient, could be explained by distention of the walls of the cyst by a sudden increase in the amount of lymph. The lack of the conventional chest x-ray film to show some pathologic image may be explained by the cyst being empty, and the fleeting density noted during barium swallow may be explained by a transient refilling of the cyst. Since a specific clinical picture has not been described for this rare entity,1Fromang DR Seltzer MB Tobias JA Thoracic duct cyst causing mediastinal compression and acute respiratory insufficiency.Chest. 1975; 67: 725-727Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar, 2Beasley WE Mills M Chylous cystectomy with prosthetic reconstruction of the diaphragm and esophageal hiatus.J Thorac Cardiovasc Surg. 1971; 61: 324-329PubMed Google Scholar we believe that the presence of thoracic pain or of symptoms of mediastinal compression in close relationship to the ingestion of a meal must be considered as very suggestive findings in the diagnosis of thoracic duct cysts of the mediastinum. Lymphangiographic studies must then be performed.