CT features of rounded atelectasis of the lung.

Rounded atelectasis is an uncommon but increasingly recognized benign form of peripheral lung collapse. The three patients described here had pleural-based lung masses considered initially to represent carcinoma. On computed tomography, a characteristic appearance of eight major and five minor signs of rounded atelectasis of the lung were found. In conjunction with other radiologic evaluations, these allowed the patients to be confidently managed without exploratory thoracotomy.