Sometimes they are called epidermal cysts on the body and pilar cysts on the scalp. Cysts are encapsulated nodules that develop from oil duct cells and contain a smelly, cheesy substance made of keratin, a skin protein. Cysts are virtually never cancerous. If they do not bother you, then ignore them. Deeper, fixed lumps are not cysts and may represent a cancer.
Most epidermal cysts have a communicating pore like a blackhead.
Some benign fatty tumors can mimic cysts. They tend to have a fleshy consistency and are called lipomas. Treatment Treatment must be individualized. Sometimes the best treatment is no treatment. A plastic surgeon may be willing to tackle these.