"True" sebaceous cysts (i.e. cysts which originate from sebaceous glands and which contain sebum) are relatively rare and are known as steatocystomas or, if multiple, as steatocystoma multiplex.
The scalp, ears, back, face, and upper arm, are common sites for sebaceous cysts, though they may occur anywhere on the body except the palms of the hands and soles of the feet. In males a common place for them to develop is the scrotum and chest. They are more common in hairier areas, where in cases of long duration they could result in hair loss on the skin surface immediately above the cyst. They are smooth to the touch, vary in size, and are generally round in shape.
