What is a cyst in dermatological terms?

A cyst, in dermatological terms, is defined as a sac-like structure that can contain fluid, air, or semi-solid material. The correct understanding of a cyst is that it typically refers to a closed pocket or sac that can form in the skin or other tissues of the body. This sac serves as a container for varying contents, which is why the identification of it as containing a "gaseous liquid" aligns with how cysts can sometimes present, particularly when considering scenarios like sebaceous cysts.

While cysts can contain different substances—such as pus, serous fluid, or even keratin—what fundamentally defines a cyst is its encapsulation within a distinct wall. In dermatology, it’s crucial to recognize what constitutes a cyst to differentiate it from other types of skin lesions or growths. Understanding this definition aids in diagnosing and treating skin conditions appropriately, as it reflects the typical clinical presentation of cystic structures in various dermatological scenarios.