Tumeurs médiastinales d'origine embryonnaire

Mediastinal tumours of embryonic origin refer to tumours resulting from a disorder of the embryonic development, or to tumours deriving from germinal cells and of which the primitive localization is the mediastinum. Such tumours are constituted by tissues similar to those that successively develop from the embryonic to the adult stage. These benign or malignant lesions are classified according to their histogenesis and the available therapeutic means. Germinal tumours are constituted by tissues similar to those that succeed one another during the development, by differentiation of primitive laminas and extraembryonic laminas. In terms of therapy, seminomas have to be distinguished from non seminomatous germinal tumours, and from teratomas. Mediastinal cysts are malformations constituted by tissues included normally into the adult thorax. They are distributed in five classes, according to their structure: bronchogenic and paraoesophageal cysts, pleuropericardic cysts, cystic lymphangiomas, benign haemangiomas, and meningeal cysts.