Rounded atelectasis due to acute exudative effusion. Spontaneous resolution.

Rounded atelectasis is an interesting roentgenographic entity that must be distinguished from intrathoracic neoplasm. Chronic pleural disease, particularly that due to asbestos exposure, is a frequently cited cause, and is considered to be a sine qua non by some. We report a case of rounded atelectasis with an acute parapneumonic exudative effusion that resolved spontaneously with roentgenographically normal pleura.