Osteochondroma of the rib: an unusual cause of haemothorax.

The case is described of a 36 year old woman who presented with a large left sided haemothorax. A thoracic computed tomographic (CT) scan suggested there was a bony outgrowth arising from the fourth rib. This was resected surgically and found to be an osteochondroma which was surrounded by blood clot. No definite site of bleeding was identified, but it is thought that the tumour may have traumatised the lung, the pericardiacophrenic artery, or the superior pulmonary vein, resulting in life threatening haemorrhage.