[Isolated cystic lymphangioma in the mediastinum].

Cystic lymphangioma localized only in the mediastinum is a rare type of primitive tumour (less than 1% of the mediastinum primitive tumours). These three new observations concern lymphangiomas with an anterior position ; therir anatomical connections with the lymphatic system are difficult to show. Treated by surgery these benign tumours have a good prognosis and only a few cases of local recurrences have been reported.