A cyst is a sac of fluid that forms a lump beneath the skin. Sebaceous cysts are hard lumps filled with keratin, the thick greasy protein which hairs are made from and which lubricates the top layer ...

Skin cyst is a sac like lesion situated beneath the skin which is filled with fluid or pus and other secretions, and enclosed by a cyst wall. The skin is made up of 2 layers, an outer layer called the ...