[Lymphangioendothelioma. A rare cause of atrioventricular block]

A new case of lymphangio-endothelioma of the nodal tissue is reported. Complete atrioventricular block had been followed up for 20 years. The histological features are described in detail and the embryological origins of the tumour are discussed. This report underlines the exceptional character of this "smallest benign tumour which can be mortal".