pilar cyst
Noun: A pilar cyst is a common, benign (non-cancerous) skin growth. It is a closed sac or capsule that forms under the skin, typically on the scalp. It is filled with a soft, fatty, cheese-like material called keratin, which is a protein that makes up hair and skin.
A pilar cyst is a specific type of cyst that originates from a hair follicle. It is often used in medical or dermatological contexts. - The dermatologist diagnosed the lump on her scalp as a pilar cyst. - Pilar cysts are usually smooth, round, and movable under the skin.
- Clinical Context: The term is used precisely to distinguish this type of cyst from other common cysts, such as epidermoid cysts. Pilar cysts are also sometimes referred to as trichilemmal cysts.
- Histological examination confirmed it was a pilar cyst, not an epidermoid cyst.
- Trichilemmal Cyst: A technical synonym for a pilar cyst, referring to its origin from the outer root sheath (trichilemma) of a hair follicle.
- Sebaceous Cyst: A common but often inaccurate lay term for various skin cysts, including pilar cysts. True sebaceous cysts are rarer.
- Trichilemmal cyst
- Wen (a non-technical, informal term sometimes used for various scalp cysts)
While the reference context mentions "filled with fatty matter (sebum)," it is important to note that pilar cysts are primarily filled with keratin, not sebum. Sebum is the oily substance secreted by sebaceous glands, which are associated with a different type of cyst. This is a key distinguishing feature.
- a common cyst of the skin; filled with fatty matter (sebum) that is secreted by a sebaceous gland that has been blocked