Can you explain what intrathoracic pathology means?

An explanation: In the broadest sense of the word, "pathology" means something that is abnormal and, in medicine, is usually inferred to be something abnormal that is harming your well-being in any way. Intrathoracic means "within the thoracic cavity." Generally speaking this is within your chest (above the diaphragm and below the neck). In short. Combine these two and you have intrathoracic pathology.

Diseases of chest: The thorax refers to the chest cavity - basically everything inside your rib cage. This includes your lungs, heart, mediastinal structures such as lymph nodes or remnant thymus, trachea (windpipe), esophagus, and vessels including portions of the aorta. So 'intrathoracic pathology' means any disorder involving any of these structures. It's a general term.