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Epidermoid cyst
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An epidermoid cyst is a cavity lined on the inside with squamous epithelium, a lining made of flat cells. That lining is not inert: it makes keratin and leaves it piling up inside, so the cavity fills with the material it produces itself, like a bag that bulges from whatever keeps getting stored in it.
Many epidermoid cysts start at the top of a hair follicle, the channel a hair comes out of. Others form when surface cells get trapped further down, in the dermis, the supporting layer underneath. If the wall of that bag breaks, the keratin spills into the surrounding tissue and can set off intense inflammation, which still does not prove there is an infection.
In brief
An epidermoid cyst is a cavity lined by squamous epithelium. This lining produces keratin, which builds up inside the cyst.
Many arise from the upper part of a hair follicle; others form when surface skin cells become trapped in the dermis, the supporting layer underneath.
If the wall ruptures, keratin spills into the surrounding tissue and can trigger intense inflammation, which by itself is not proof of infection.
The cyst has a wall and a keratin-filled center. When it ruptures, the contents reach the surrounding tissue and trigger inflammation.
Sources (2)
- National Library of MedicineEpidermal Inclusion Cyst
- European Journal of Radiology OpenOverview of epidermoid cystPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
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