What is a circumscribed collection of pus surrounded by a wall of inflammatory tissues called?

A circumscribed collection of pus surrounded by a wall of inflammatory tissues is referred to as an abscess. An abscess forms as a result of the body's response to an infection, where the immune system sends white blood cells to the site of infection. This process leads to the accumulation of pus, which consists of dead tissue, bacteria, and white blood cells. The inflammatory response results in the formation of a fibrous capsule around the pus, effectively isolating it from the surrounding tissues.

This encapsulation is what distinguishes an abscess from other types of fluid collections. In contrast, edema refers to swelling caused by excess fluid in the tissues, a vesicle is a small fluid-filled lesion, and infiltrate generally describes the presence of an abnormal substance within tissues but does not specifically refer to pus or inflammation. Therefore, the correct description of a localized collection of pus within an inflammatory wall aligns with the definition of an abscess.