In paraseptal emphysema, where is the dilation, primarily found?

In paraseptal emphysema, the dilation primarily occurs in the distal acinus, particularly near the pleura. This form of emphysema is characterized by the destruction of the alveolar walls in the terminal airspaces, leading to the formation of enlarged airspaces or bullae. These changes are often localized to the peripheral regions of the lungs, particularly along the pleural surfaces.

The pathology is typically related to the effects of smoking or other environmental factors that result in inflammation and damage to the lung parenchyma. This localized dilation impacts the distal acinar units, which are located at the end of the conducting airways and includes structures such as alveoli. In contrast, other emphysema types, like centriacinar emphysema, affect more central airways and proximal regions.

Recognizing the specific location of dilation in paraseptal emphysema is vital for understanding its clinical implications and distinguishing it from other types of emphysema, which may present different patterns of lung involvement and pathology.