[1st reported case of pneumothorax caused by sternal puncture].

The case of a woman aged 65 who presented pneumothorax following sternal marrow needle biopsy after diagnosis of thrombocytosis is reported. The complication was certainly attributable to the biopsy because chest X-ray immediately prior had been perfectly normal. No other cases of the kind have been reported. It is probable that this complication occurred because air passed into the pleural cavity, probably through a fracture rim at the internal face of the sternal bone trabeculae.