Retained intrathoracic surgical swab: CT appearances.

A retained surgical swab (gossypiboma) is a rare but important complication of intrathoracic surgery. The radiographic and computed tomography (CT) appearances are variable and depend on the chronicity and site of the swab within the chest. Two cases of retained swabs within the chest are reported. In both cases, the swab had become surrounded by lung. The swab within the pleural space acted as a nidus and resulted in infolding of the lung, superficially resembling an intrapulmonary abscess on CT.