What condition is characterized by air or gas in the pleural space?

The condition characterized by air or gas in the pleural space is pneumothorax. This situation arises when air enters the pleural cavity, which is the space between the layers of tissue lining the lungs and the chest wall. The presence of air in this space can cause the lung to collapse partially or completely, leading to difficulty in breathing and chest pain, as well as potentially serious complications if not treated promptly.

Pneumothorax can occur spontaneously, due to injury, or as a consequence of medical procedures. Recognizing pneumothorax is crucial for pathologists and healthcare providers, as it typically requires immediate diagnostic imaging and intervention to restore normal pleural pressure and function. Understanding the distinction between pneumothorax and other conditions is important, as they involve different pathophysiological processes and clinical management.