. (1974). Thorax, 29,[215][216][217][218][219][220][221][222] (Fig. 2). She had no symptoms. On examination caf6-au-lait patches and several neurofibromata were found on the skin. The chest radiograph showed a convex opacity arising from the left side of the mediastinum at the level of the aortic arch and left hilum. It had a clearly defined smooth lateral margin which merged with the aortic arch but seemed separate from the left hilum. A lateral view and tomography indicated a central mediastinal mass bulging downwards and backwards behind the left hilum beneath the aortic arch. A barium swallow and aortogram were normal. At thoracotomy several tumours were found arising from the left vagus nerve. There were four main tumour masses in that part of the nerve between the thoracic inlet and left lung hilum. A further small tumour was present at the lower end of the intrathoracic vagus immediately above the diaphragm. Two small tumour nodules were also present on the phrenic nerve as it coursed over the heart. The portions of the vagus and phrenic nerves involved by the tumours were resected. Histology showed the tumours to be neurofibromata.