Cystic hygroma of the mediastinum.

The rarity with which cystic hygroma occurs in, and is confined to, the mediastinum justifies the report of a further case. Gross and Hurwitt (1948), after a careful review of the literature, were able to find only seven cases which they regarded as undoubted cystic hygromata, and they added a further one of their own. The author has excluded one of the cases collected by these authors, namely that reported by Eliaschewitsch (1929), in which a unilocular pedunculated cyst was found inside the pericardial cavity at post-mortem examination performed on a patient who had suffered from chronic endocarditis and fibrinous pericarditis. The case reported here thus brings the total to eight. Blades (1946) found no case of cystic hygroma amongst the 109 patients with mediastinal tumours collected from various Army chest centres, while Watson and Diamond (1947) found only one in Navy personnel. Cervico-mediastinal hygromata, though rare, are more common than are those confined to the chest. Gross and Hurwitt (1948) collected 19 such cases from the literature, and added two of their own to make a total of 21.