benign (not cancerous), slow-growing tumors that come from fat cells. They are usually round, moveable, flattened lumps
under the
skin. They feel soft and doughy or rubbery. Lipomas usually grow in the neck, shoulders, back, or arms. Lipomas are the most common noncancerous tumor in adults. They can occur at any age, but they often appear when you're between 40 and 60 years of age. Sometimes they run in families. Sometimes they are caused by an injury.