A sebaceous cyst is a closed sac under the skin filled with a cheese-like or oily material. Sebaceous cysts
are commonly seen on the scalp, labia, scrotum, chest, and back, but
can be found anywhere on the body. A foul odor is also often present in
the substance called keratin which fills sebaceous cysts.
Keratin is a protein that creates the sac of cells called sebaceous cysts. The bumps or lumps you can feel under your skin are actually the sac of cells. Sebaceous cysts
are often the result of swollen hair follicles, or skin trauma. The
scalp, ears, back, face, and upper arm, are common...