Patients always want to be told by their doctor that something is all right and leave it alone. The truth is that a lump could turn into a bigger problem.
A sebaceous cyst is a sac-like structure just under the skin that contains a cheese-like material called sebum. These cysts can be infected easily and without warning, which can then lead to cellulitis, a serious skin infection that can spread quickly. In a diabetic, for example, this simple infection could be disastrous. A sebaceous cyst will never go away without surgical removal of the sac. A cyst can be drained, but the sac will remain and can fill up again, and become infected. Once a sebaceous cyst is removed, it will never come back.
A lipoma is a benign soft tissue tumor made up of body fat. They are the most common of soft tissue tumors, and can occur on any skin surface area. As lipomas increase in size though, there have been cases in which malignant (cancerous) transformation has occurred. Approximately 1 percent of the population has a lipoma, and they can occur at any age but most often in age ranges of 40-60 years old. The possibility of a lipoma undergoing a malignant change to a liposarcoma is why most tumors should be removed. The definitive characteristics of a lump are not fully known until it is removed and examined under a microscope.