Encyclopedia Home / S / Sebaceous cyst

Sebaceous cyst

  • Definition

    A sebaceous cyst is a closed sac under the skin filled with a cheese-like or oily material.

    See also:

    • Carbuncle
    • Cyst
    • Furuncle

    Alternative Names

    Epidermal cyst; Keratin cyst; Epidermoid cyst


    Causes, incidence, and risk factors

    Sebaceous cysts most often arise from swollen hair follicles. Skin trauma can also induce a cyst to form. A sac of cells is created into which a protein called keratin is secreted.

    These cysts are usually found on the face, neck, and trunk. They are usually slow- growing, painless, freely movable lumps beneath the skin. Occasionally, however, a cyst will become inflamed and tender.