A 75 year old man who had had haemoptysis for 24 hours was found to have his left lower lobe compressed by a dissection of the aorta, which was otherwise symptomless.Haemoptysis is a rare complication of aortic dissection, and recurrent haemoptysis as the sole initial symptom is most unusual. We report such a case. Case reportA 75 year old man was admitted to our department because of recurrent haemoptysis of 24 hours' duration. His medical history included hypertension and mild diabetes mellitus of five years' duration. He had been admitted to hospital two years earlier because of recurrent transient ischaemic attacks.The patient was symptomless and on physical examination was generally well, without dyspnoea or chest pain. The pulse was regular at 100 beats/min and the blood pressure was 160/ 110 mm Hg. No murmurs were heard over the heart; breath sounds were diminished over the lower part of the left lung. The femoral arteries were palpated but peripheral pulses were absent.The pertinent laboratory data included packed cell volume (0 51) and prothrombin time, platelet count, and creatinine concentration, which were all within the normal range. No acid fast bacilli were identified in sputum.An initial chest radiograph showed a tortuous and enlarged aorta with a questionable double contour at the left edge of the aortic arch. Computed tomography showed an enlarged aneurysmal aorta with an intimal flap (fig 1). Irregular crowding of the lower left lobe due to compression by the aneurysm was also seen (fig 2). Subsequent angiography confirmed dissection of the descending aorta. At bronchoscopy the only abnormal finding was a clot in the left lower lobe bronchus.The patient refused surgical intervention. Paraparesis developed and he died two weeks later in uraemic coma. Postmortem examination showed dissection of the descending aorta beyond the origin of the left subclavian artery, adhesions ofthe aneurysm along the left lung, and an infected area in the lung adjacent to the aneurysm.