Toxic Synergism of Disopyramide

CHEST, 78: 4, OCTOBER, 1980 Only eight cases diagnosed during life as a cyst of the thoracic duct have been reported.’3’59 Although Steinberg and Watson1#{176} reported some cases with a jugular lymph sac at the site of entrance of lymphatic channels into the vein, these cases were thought to be different from the other reported cases. Steinberg and Watson’#{176}concluded that a persistent embryonic jugular lymph sac may become evident in the neck because of incompetence or absence of valves. The case reported by Barlow and Gracey4 may have the same etiology as a jugular lymph sac. Histologically, our case had inflammatory changes which indicated an acquired origin. In addition, several reports mentioned atherosclerotic or inflammatory changes in the wall of the cyst.4’5’7’9 Considering some congenital factors, the origin of cysts of the thoracic duct remains the subject of debate. Although some cases have been reported as a symptomless”2’ ’6’ pain in the chest, dyspnea, and dysphagia apparently due to the mediastinal compression by the cyst were significant in our case. An increase in symptoms after meals, as mentioned by CervantesPerez and Fuentes-Maldonado,9 is important and a clue to this diagnosis, but there was no close relationship to the ingestion of a meal in our case. Lymphangiographic studies should be strongly recommended for posterior mediastinal masses when other diagnostic methods fail to make a diagnosis. Surgery may be unnecessary for a symptomless case. A cyst of the thoracic duct should be included in the list of differential possibilities for posterior mediastinal masses.