Dieulafoy's disease of the lung: a potential disaster for the bronchoscopist.

Dieulafoy's disease of the lung is very rare. We present 2 cases, which are, to our knowledge, the 9th and 10th cases reported in the literature. Haemoptysis is the leading symptom of Dieulafoy's lesion of the lung. In spite of its rareness, the lesion is relevant to the bronchoscopist because a biopsy of the unobtrusive but characteristic bronchial manifestation can precipitate profuse arterial bleeding with a fatal outcome. The bleeding can occur immediately after the biopsy and/or after an interval of up to 12 days. Angiographic images document that this vascular malformation is based on a left-to-right shunt, with a bronchial artery draining into a pulmonary artery. Endobronchial ultrasound may be helpful in detecting the vascular nature of the lesion.